64121640 has 128 divisors (see below), whose sum is σ = 216760320. Its totient is φ = 15033600.

The previous prime is 64121633. The next prime is 64121641. The reversal of 64121640 is 4612146.

64121640 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×64121640² = 8223169432579200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 64121640.

It is not an unprimeable number, because it can be changed into a prime (64121641) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 40137 + ... + 41703.

It is an arithmetic number, because the mean of its divisors is an integer number (1693440).

Almost surely, 2^64121640 is an apocalyptic number.

64121640 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 64121640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (108380160).

64121640 is an abundant number, since it is smaller than the sum of its proper divisors (152638680).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

64121640 is a wasteful number, since it uses less digits than its factorization.

64121640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1623 (or 1619 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 24.

The square root of 64121640 is about 8007.5988910534. The cubic root of 64121640 is about 400.2532562860.

Adding to 64121640 its reverse (4612146), we get a palindrome (68733786).

The spelling of 64121640 in words is "sixty-four million, one hundred twenty-one thousand, six hundred forty".