64420440 has 128 divisors (see below), whose sum is σ = 225192960. Its totient is φ = 14436864.

The previous prime is 64420427. The next prime is 64420451. The reversal of 64420440 is 4402446.

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 64420440.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 43797 + ... + 45243.

It is an arithmetic number, because the mean of its divisors is an integer number (1759320).

Almost surely, 2^64420440 is an apocalyptic number.

64420440 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 64420440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (112596480).

64420440 is an abundant number, since it is smaller than the sum of its proper divisors (160772520).

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

64420440 is a wasteful number, since it uses less digits than its factorization.

64420440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1521 (or 1517 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 24.

The square root of 64420440 is about 8026.2344844890. The cubic root of 64420440 is about 400.8740055614.

Adding to 64420440 its reverse (4402446), we get a palindrome (68822886).

The spelling of 64420440 in words is "sixty-four million, four hundred twenty thousand, four hundred forty".