191231994756 has 144 divisors (see below), whose sum is σ = 529120247040. Its totient is φ = 53271482880.

The previous prime is 191231994697. The next prime is 191231994757. The reversal of 191231994756 is 657499132191.

It is a super-2 number, since 2×191231994756² (a number of 23 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 191231994696 and 191231994705.

It is not an unprimeable number, because it can be changed into a prime (191231994757) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1582075 + ... + 1698653.

It is an arithmetic number, because the mean of its divisors is an integer number (3674446160).

Almost surely, 2^191231994756 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 191231994756, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (264560123520).

191231994756 is an abundant number, since it is smaller than the sum of its proper divisors (337888252284).

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

191231994756 is a wasteful number, since it uses less digits than its factorization.

191231994756 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 116674 (or 116655 counting only the distinct ones).

The product of its digits is 3674160, while the sum is 57.

The spelling of 191231994756 in words is "one hundred ninety-one billion, two hundred thirty-one million, nine hundred ninety-four thousand, seven hundred fifty-six".