64636540 has 24 divisors (see below), whose sum is σ = 135913680. Its totient is φ = 25820928.

The previous prime is 64636493. The next prime is 64636543. The reversal of 64636540 is 4563646.

It is a junction number, because it is equal to n+sod(n) for n = 64636496 and 64636505.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64636543) 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, 18579 + ... + 21781.

It is an arithmetic number, because the mean of its divisors is an integer number (5663070).

Almost surely, 2^64636540 is an apocalyptic number.

It is an amenable number.

64636540 is an abundant number, since it is smaller than the sum of its proper divisors (71277140).

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

64636540 is a wasteful number, since it uses less digits than its factorization.

64636540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4221 (or 4219 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 34.

The square root of 64636540 is about 8039.6853172248. The cubic root of 64636540 is about 401.3217526144.

The spelling of 64636540 in words is "sixty-four million, six hundred thirty-six thousand, five hundred forty".