661867272 has 96 divisors (see below), whose sum is σ = 1984862880. Its totient is φ = 197556480.

The previous prime is 661867253. The next prime is 661867303. The reversal of 661867272 is 272768166.

661867272 is a `hidden beast` number, since 6 + 618 + 6 + 7 + 27 + 2 = 666.

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, 46828 + ... + 59300.

It is an arithmetic number, because the mean of its divisors is an integer number (20675655).

Almost surely, 2^661867272 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 661867272, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (992431440).

661867272 is an abundant number, since it is smaller than the sum of its proper divisors (1322995608).

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

661867272 is a wasteful number, since it uses less digits than its factorization.

661867272 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12563 (or 12556 counting only the distinct ones).

The product of its digits is 338688, while the sum is 45.

The square root of 661867272 is about 25726.7812211322. The cubic root of 661867272 is about 871.4790852534.

The spelling of 661867272 in words is "six hundred sixty-one million, eight hundred sixty-seven thousand, two hundred seventy-two".