661555624 has 32 divisors (see below), whose sum is σ = 1336112640. Its totient is φ = 306187200.

The previous prime is 661555619. The next prime is 661555649. The reversal of 661555624 is 426555166.

661555624 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its 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, 52287 + ... + 63694.

It is an arithmetic number, because the mean of its divisors is an integer number (41753520).

Almost surely, 2^661555624 is an apocalyptic number.

It is an amenable number.

661555624 is an abundant number, since it is smaller than the sum of its proper divisors (674557016).

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

661555624 is a wasteful number, since it uses less digits than its factorization.

661555624 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 116041 (or 116037 counting only the distinct ones).

The product of its digits is 216000, while the sum is 40.

The square root of 661555624 is about 25720.7236290117. The cubic root of 661555624 is about 871.3422817157.

The spelling of 661555624 in words is "six hundred sixty-one million, five hundred fifty-five thousand, six hundred twenty-four".