191012557 has 2 divisors, whose sum is σ = 191012558. Its totient is φ = 191012556.

The previous prime is 191012551. The next prime is 191012593. The reversal of 191012557 is 755210191.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 177129481 + 13883076 = 13309^2 + 3726^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-191012557 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (191012551) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 95506278 + 95506279.

It is an arithmetic number, because the mean of its divisors is an integer number (95506279).

Almost surely, 2^191012557 is an apocalyptic number.

It is an amenable number.

191012557 is a deficient number, since it is larger than the sum of its proper divisors (1).

191012557 is an equidigital number, since it uses as much as digits as its factorization.

191012557 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3150, while the sum is 31.

The square root of 191012557 is about 13820.7292499347. The cubic root of 191012557 is about 575.9091422485.

The spelling of 191012557 in words is "one hundred ninety-one million, twelve thousand, five hundred fifty-seven".