191251891660 has 24 divisors (see below), whose sum is σ = 414584747136. Its totient is φ = 74032990080.

The previous prime is 191251891643. The next prime is 191251891679. The reversal of 191251891660 is 66198152191.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 154234777 + ... + 154236016.

It is an arithmetic number, because the mean of its divisors is an integer number (17274364464).

Almost surely, 2^191251891660 is an apocalyptic number.

191251891660 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

191251891660 is an abundant number, since it is smaller than the sum of its proper divisors (223332855476).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

191251891660 is a wasteful number, since it uses less digits than its factorization.

191251891660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 308470833 (or 308470831 counting only the distinct ones).

The product of its (nonzero) digits is 233280, while the sum is 49.

The spelling of 191251891660 in words is "one hundred ninety-one billion, two hundred fifty-one million, eight hundred ninety-one thousand, six hundred sixty".