661115600 has 30 divisors (see below), whose sum is σ = 1588331190. Its totient is φ = 264446080.

The previous prime is 661115573. The next prime is 661115633. The reversal of 661115600 is 6511166.

It can be written as a sum of positive squares in 3 ways, for example, as 117852736 + 543262864 = 10856^2 + 23308^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 661115600.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 825995 + ... + 826794.

It is an arithmetic number, because the mean of its divisors is an integer number (52944373).

Almost surely, 2^661115600 is an apocalyptic number.

It is an amenable number.

661115600 is an abundant number, since it is smaller than the sum of its proper divisors (927215590).

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

661115600 is a wasteful number, since it uses less digits than its factorization.

661115600 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1652807 (or 1652796 counting only the distinct ones).

The product of its (nonzero) digits is 1080, while the sum is 26.

The square root of 661115600 is about 25712.1683255225. The cubic root of 661115600 is about 871.1490520307.

Adding to 661115600 its reverse (6511166), we get a palindrome (667626766).

The spelling of 661115600 in words is "six hundred sixty-one million, one hundred fifteen thousand, six hundred".