661158208251 has 24 divisors (see below), whose sum is σ = 962616511584. Its totient is φ = 437264012160.

The previous prime is 661158208223. The next prime is 661158208259. The reversal of 661158208251 is 152802851166.

661158208251 is a `hidden beast` number, since 6 + 6 + 11 + 582 + 0 + 8 + 2 + 51 = 666.

It is not a de Polignac number, because 661158208251 - 2³⁰ = 660084466427 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 661158208197 and 661158208206.

It is not an unprimeable number, because it can be changed into a prime (661158208259) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1685625 + ... + 2040501.

It is an arithmetic number, because the mean of its divisors is an integer number (40109021316).

Almost surely, 2^661158208251 is an apocalyptic number.

661158208251 is a deficient number, since it is larger than the sum of its proper divisors (301458303333).

661158208251 is a wasteful number, since it uses less digits than its factorization.

661158208251 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 356531 (or 356528 counting only the distinct ones).

The product of its (nonzero) digits is 230400, while the sum is 45.

The spelling of 661158208251 in words is "six hundred sixty-one billion, one hundred fifty-eight million, two hundred eight thousand, two hundred fifty-one".