661623724 has 24 divisors (see below), whose sum is σ = 1202808096. Its totient is φ = 318192000.

The previous prime is 661623713. The next prime is 661623763. The reversal of 661623724 is 427326166.

It is a hoax number, since the sum of its digits (37) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 16767 + ... + 40054.

It is an arithmetic number, because the mean of its divisors is an integer number (50117004).

Almost surely, 2^661623724 is an apocalyptic number.

It is an amenable number.

661623724 is a deficient number, since it is larger than the sum of its proper divisors (541184372).

661623724 is a wasteful number, since it uses less digits than its factorization.

661623724 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 56937 (or 56935 counting only the distinct ones).

The product of its digits is 72576, while the sum is 37.

The square root of 661623724 is about 25722.0474301717. The cubic root of 661623724 is about 871.3721791127.

The spelling of 661623724 in words is "six hundred sixty-one million, six hundred twenty-three thousand, seven hundred twenty-four".