65531006640 has 320 divisors, whose sum is σ = 254183731200. Its totient is φ = 15373670400.

The previous prime is 65531006633. The next prime is 65531006677. The reversal of 65531006640 is 4660013556.

65531006640 is a `hidden beast` number, since 6 + 5 + 5 + 3 + 1 + 0 + 0 + 6 + 640 = 666.

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

It is a junction number, because it is equal to n+sod(n) for n = 65531006595 and 65531006604.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 692076 + ... + 781044.

It is an arithmetic number, because the mean of its divisors is an integer number (794324160).

Almost surely, 2^65531006640 is an apocalyptic number.

65531006640 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 65531006640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (127091865600).

65531006640 is an abundant number, since it is smaller than the sum of its proper divisors (188652724560).

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

65531006640 is a wasteful number, since it uses less digits than its factorization.

65531006640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 89033 (or 89021 counting only the distinct ones).

The product of its (nonzero) digits is 64800, while the sum is 36.

The spelling of 65531006640 in words is "sixty-five billion, five hundred thirty-one million, six thousand, six hundred forty".