65640636 has 72 divisors (see below), whose sum is σ = 171426528. Its totient is φ = 21168000.

The previous prime is 65640629. The next prime is 65640647. The reversal of 65640636 is 63604656.

65640636 is a `hidden beast` number, since 6 + 5 + 640 + 6 + 3 + 6 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 65640636.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 155706 + ... + 156126.

It is an arithmetic number, because the mean of its divisors is an integer number (2380924).

Almost surely, 2^65640636 is an apocalyptic number.

65640636 is the 4331-st nonagonal number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 65640636, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (85713264).

65640636 is an abundant number, since it is smaller than the sum of its proper divisors (105785892).

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

65640636 is a wasteful number, since it uses less digits than its factorization.

65640636 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 563 (or 558 counting only the distinct ones).

The product of its (nonzero) digits is 77760, while the sum is 36.

The square root of 65640636 is about 8101.8908904033. The cubic root of 65640636 is about 403.3891939721.

The spelling of 65640636 in words is "sixty-five million, six hundred forty thousand, six hundred thirty-six".