661016563625 has 16 divisors (see below), whose sum is σ = 899944007040. Its totient is φ = 480739318000.

The previous prime is 661016563621. The next prime is 661016563643. The reversal of 661016563625 is 526365610166.

It is not a de Polignac number, because 661016563625 - 2² = 661016563621 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 661016563625.

It is not an unprimeable number, because it can be changed into a prime (661016563621) 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, 240368285 + ... + 240371034.

It is an arithmetic number, because the mean of its divisors is an integer number (56246500440).

Almost surely, 2^661016563625 is an apocalyptic number.

It is an amenable number.

661016563625 is a deficient number, since it is larger than the sum of its proper divisors (238927443415).

661016563625 is a wasteful number, since it uses less digits than its factorization.

661016563625 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 480739345 (or 480739335 counting only the distinct ones).

The product of its (nonzero) digits is 1166400, while the sum is 47.

The spelling of 661016563625 in words is "six hundred sixty-one billion, sixteen million, five hundred sixty-three thousand, six hundred twenty-five".