661915924 has 6 divisors (see below), whose sum is σ = 1158352874. Its totient is φ = 330957960.

The previous prime is 661915921. The next prime is 661915951. The reversal of 661915924 is 429519166.

It can be written as a sum of positive squares in only one way, i.e., 415425924 + 246490000 = 20382^2 + 15700^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661915921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82739487 + ... + 82739494.

Almost surely, 2^661915924 is an apocalyptic number.

It is an amenable number.

661915924 is a deficient number, since it is larger than the sum of its proper divisors (496436950).

661915924 is a wasteful number, since it uses less digits than its factorization.

661915924 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 165478985 (or 165478983 counting only the distinct ones).

The product of its digits is 116640, while the sum is 43.

The square root of 661915924 is about 25727.7267553898. The cubic root of 661915924 is about 871.5004380550.

The spelling of 661915924 in words is "six hundred sixty-one million, nine hundred fifteen thousand, nine hundred twenty-four".