11891981690 has 8 divisors (see below), whose sum is σ = 21405567060. Its totient is φ = 4756792672.

The previous prime is 11891981681. The next prime is 11891981701. The reversal of 11891981690 is 9618919811.

It can be written as a sum of positive squares in 2 ways, for example, as 10970677081 + 921304609 = 104741^2 + 30353^2 .

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

It is a super-2 number, since 2×11891981690² (a number of 21 digits) contains 22 as substring.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 594599075 + ... + 594599094.

Almost surely, 2^11891981690 is an apocalyptic number.

11891981690 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

11891981690 is a deficient number, since it is larger than the sum of its proper divisors (9513585370).

11891981690 is a wasteful number, since it uses less digits than its factorization.

11891981690 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1189198176.

The product of its (nonzero) digits is 279936, while the sum is 53.

The spelling of 11891981690 in words is "eleven billion, eight hundred ninety-one million, nine hundred eighty-one thousand, six hundred ninety".