64539640 has 32 divisors (see below), whose sum is σ = 158416560. Its totient is φ = 23468800.

The previous prime is 64539589. The next prime is 64539641. The reversal of 64539640 is 4693546.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 64539640.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64539641) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 72901 + ... + 73780.

Almost surely, 2^64539640 is an apocalyptic number.

It is an amenable number.

64539640 is an abundant number, since it is smaller than the sum of its proper divisors (93876920).

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

64539640 is a wasteful number, since it uses less digits than its factorization.

64539640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 146703 (or 146699 counting only the distinct ones).

The product of its (nonzero) digits is 77760, while the sum is 37.

The square root of 64539640 is about 8033.6567016521. The cubic root of 64539640 is about 401.1211048740.

The spelling of 64539640 in words is "sixty-four million, five hundred thirty-nine thousand, six hundred forty".