191897921013 has 8 divisors (see below), whose sum is σ = 256353120288. Its totient is φ = 127687334544.

The previous prime is 191897921003. The next prime is 191897921081. The reversal of 191897921013 is 310129798191.

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

It is not a de Polignac number, because 191897921013 - 2²⁵ = 191864366581 is a prime.

It is a super-2 number, since 2×191897921013² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (191897921003) 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, 61151370 + ... + 61154507.

It is an arithmetic number, because the mean of its divisors is an integer number (32044140036).

Almost surely, 2^191897921013 is an apocalyptic number.

It is an amenable number.

191897921013 is a deficient number, since it is larger than the sum of its proper divisors (64455199275).

191897921013 is a wasteful number, since it uses less digits than its factorization.

191897921013 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 122306403.

The product of its (nonzero) digits is 244944, while the sum is 51.

The spelling of 191897921013 in words is "one hundred ninety-one billion, eight hundred ninety-seven million, nine hundred twenty-one thousand, thirteen".