661315536 has 160 divisors (see below), whose sum is σ = 2244499200. Its totient is φ = 182407680.

The previous prime is 661315511. The next prime is 661315547. The reversal of 661315536 is 635513166.

661315536 is a `hidden beast` number, since 6 + 613 + 1 + 5 + 5 + 36 = 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 661315536.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 83926 + ... + 91466.

It is an arithmetic number, because the mean of its divisors is an integer number (14028120).

Almost surely, 2^661315536 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 661315536, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1122249600).

661315536 is an abundant number, since it is smaller than the sum of its proper divisors (1583183664).

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

661315536 is a wasteful number, since it uses less digits than its factorization.

661315536 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7594 (or 7582 counting only the distinct ones).

The product of its digits is 48600, while the sum is 36.

The square root of 661315536 is about 25716.0559962060. The cubic root of 661315536 is about 871.2368614354.

The spelling of 661315536 in words is "six hundred sixty-one million, three hundred fifteen thousand, five hundred thirty-six".