661925500921 has 16 divisors (see below), whose sum is σ = 697560413760. Its totient is φ = 626370736320.

The previous prime is 661925500913. The next prime is 661925500937. The reversal of 661925500921 is 129005529166.

It is a cyclic number.

It is not a de Polignac number, because 661925500921 - 2³ = 661925500913 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (661925500721) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 70857711 + ... + 70867051.

It is an arithmetic number, because the mean of its divisors is an integer number (43597525860).

Almost surely, 2^661925500921 is an apocalyptic number.

It is an amenable number.

661925500921 is a deficient number, since it is larger than the sum of its proper divisors (35634912839).

661925500921 is a wasteful number, since it uses less digits than its factorization.

661925500921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13224.

The product of its (nonzero) digits is 291600, while the sum is 46.

The spelling of 661925500921 in words is "six hundred sixty-one billion, nine hundred twenty-five million, five hundred thousand, nine hundred twenty-one".