661957632 has 264 divisors, whose sum is σ = 2261722112. Its totient is φ = 182476800.

The previous prime is 661957631. The next prime is 661957633. The reversal of 661957632 is 236759166.

661957632 is a `hidden beast` number, since 6 + 6 + 1 + 9 + 5 + 7 + 632 = 666.

It is an interprime number because it is at equal distance from previous prime (661957631) and next prime (661957633).

It is not an unprimeable number, because it can be changed into a prime (661957631) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1999707 + ... + 2000037.

Almost surely, 2^661957632 is an apocalyptic number.

661957632 is a gapful number since it is divisible by the number (62) 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 661957632, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1130861056).

661957632 is an abundant number, since it is smaller than the sum of its proper divisors (1599764480).

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

661957632 is a wasteful number, since it uses less digits than its factorization.

661957632 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 395 (or 374 counting only the distinct ones).

The product of its digits is 408240, while the sum is 45.

The square root of 661957632 is about 25728.5373078222. The cubic root of 661957632 is about 871.5187423822.

The spelling of 661957632 in words is "six hundred sixty-one million, nine hundred fifty-seven thousand, six hundred thirty-two".