656958991 has 12 divisors (see below), whose sum is σ = 746695992. Its totient is φ = 574502544.

The previous prime is 656958983. The next prime is 656959001. The reversal of 656958991 is 199859656.

It is not a de Polignac number, because 656958991 - 2³ = 656958983 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (656958941) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 65301 + ... + 74686.

It is an arithmetic number, because the mean of its divisors is an integer number (62224666).

Almost surely, 2^656958991 is an apocalyptic number.

656958991 is a deficient number, since it is larger than the sum of its proper divisors (89737001).

656958991 is a wasteful number, since it uses less digits than its factorization.

656958991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 140038 (or 140019 counting only the distinct ones).

The product of its digits is 5248800, while the sum is 58.

The square root of 656958991 is about 25631.2112667349. The cubic root of 656958991 is about 869.3194973648.

The spelling of 656958991 in words is "six hundred fifty-six million, nine hundred fifty-eight thousand, nine hundred ninety-one".