191951630557 has 4 divisors (see below), whose sum is σ = 192184865440. Its totient is φ = 191718395676.

The previous prime is 191951630537. The next prime is 191951630597. The reversal of 191951630557 is 755036159191.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 755036159191 = 68171 ⋅11075621.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-191951630557 is a prime.

It is a super-2 number, since 2×191951630557² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (191951630537) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 116616207 + ... + 116617852.

It is an arithmetic number, because the mean of its divisors is an integer number (48046216360).

Almost surely, 2^191951630557 is an apocalyptic number.

It is an amenable number.

191951630557 is a deficient number, since it is larger than the sum of its proper divisors (233234883).

191951630557 is an equidigital number, since it uses as much as digits as its factorization.

191951630557 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 233234882.

The product of its (nonzero) digits is 1275750, while the sum is 52.

The spelling of 191951630557 in words is "one hundred ninety-one billion, nine hundred fifty-one million, six hundred thirty thousand, five hundred fifty-seven".