64439720 has 16 divisors (see below), whose sum is σ = 144989460. Its totient is φ = 25775872.

The previous prime is 64439699. The next prime is 64439723. The reversal of 64439720 is 2793446.

It can be written as a sum of positive squares in 2 ways, for example, as 61999876 + 2439844 = 7874^2 + 1562^2 .

It is not an unprimeable number, because it can be changed into a prime (64439723) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 805457 + ... + 805536.

Almost surely, 2^64439720 is an apocalyptic number.

It is an amenable number.

64439720 is an abundant number, since it is smaller than the sum of its proper divisors (80549740).

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

64439720 is a wasteful number, since it uses less digits than its factorization.

64439720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1611004 (or 1611000 counting only the distinct ones).

The product of its (nonzero) digits is 36288, while the sum is 35.

The square root of 64439720 is about 8027.4354559847. The cubic root of 64439720 is about 400.9139932833.

The spelling of 64439720 in words is "sixty-four million, four hundred thirty-nine thousand, seven hundred twenty".