191631920257 has 8 divisors (see below), whose sum is σ = 198007752960. Its totient is φ = 185268222480.

The previous prime is 191631920251. The next prime is 191631920287. The reversal of 191631920257 is 752029136191.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-191631920257 is a prime.

It is a super-2 number, since 2×191631920257² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (191631920251) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3001618 + ... + 3064795.

It is an arithmetic number, because the mean of its divisors is an integer number (24750969120).

Almost surely, 2^191631920257 is an apocalyptic number.

It is an amenable number.

191631920257 is a deficient number, since it is larger than the sum of its proper divisors (6375832703).

191631920257 is a wasteful number, since it uses less digits than its factorization.

191631920257 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6067463.

The product of its (nonzero) digits is 204120, while the sum is 46.

The spelling of 191631920257 in words is "one hundred ninety-one billion, six hundred thirty-one million, nine hundred twenty thousand, two hundred fifty-seven".