64137640 has 64 divisors (see below), whose sum is σ = 166089600. Its totient is φ = 21835008.

The previous prime is 64137599. The next prime is 64137643. The reversal of 64137640 is 4673146.

64137640 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 2×64137640² = 8227273729539200, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (64137643) 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 15 ways as a sum of consecutive naturals, for example, 43231 + ... + 44689.

It is an arithmetic number, because the mean of its divisors is an integer number (2595150).

Almost surely, 2^64137640 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 64137640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (83044800).

64137640 is an abundant number, since it is smaller than the sum of its proper divisors (101951960).

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

64137640 is a wasteful number, since it uses less digits than its factorization.

64137640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1634 (or 1630 counting only the distinct ones).

The product of its (nonzero) digits is 12096, while the sum is 31.

The square root of 64137640 is about 8008.5978797790. The cubic root of 64137640 is about 400.2865446813.

The spelling of 64137640 in words is "sixty-four million, one hundred thirty-seven thousand, six hundred forty".