131771991 has 32 divisors (see below), whose sum is σ = 202309632. Its totient is φ = 75651840.

The previous prime is 131771987. The next prime is 131771993. The reversal of 131771991 is 199177131.

It is not a de Polignac number, because 131771991 - 2² = 131771987 is a prime.

It is a super-2 number, since 2×131771991² = 34727715224208162, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (131771993) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 34986 + ... + 38568.

It is an arithmetic number, because the mean of its divisors is an integer number (6322176).

Almost surely, 2^131771991 is an apocalyptic number.

131771991 is a deficient number, since it is larger than the sum of its proper divisors (70537641).

131771991 is a wasteful number, since it uses less digits than its factorization.

131771991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3663.

The product of its digits is 11907, while the sum is 39.

The square root of 131771991 is about 11479.1981862846. The cubic root of 131771991 is about 508.8710012079.

The spelling of 131771991 in words is "one hundred thirty-one million, seven hundred seventy-one thousand, nine hundred ninety-one".