191138174021 has 4 divisors (see below), whose sum is σ = 191139598944. Its totient is φ = 191136749100.

The previous prime is 191138173987. The next prime is 191138174027. The reversal of 191138174021 is 120471831191.

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.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-191138174021 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 (191138174027) 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, 487595 + ... + 787416.

It is an arithmetic number, because the mean of its divisors is an integer number (47784899736).

Almost surely, 2^191138174021 is an apocalyptic number.

It is an amenable number.

191138174021 is a deficient number, since it is larger than the sum of its proper divisors (1424923).

191138174021 is a wasteful number, since it uses less digits than its factorization.

191138174021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1424922.

The product of its (nonzero) digits is 12096, while the sum is 38.

The spelling of 191138174021 in words is "one hundred ninety-one billion, one hundred thirty-eight million, one hundred seventy-four thousand, twenty-one".