82991431 has 2 divisors, whose sum is σ = 82991432. Its totient is φ = 82991430.

The previous prime is 82991413. The next prime is 82991443. The reversal of 82991431 is 13419928.

Together with previous prime (82991413) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 82991431 - 2⁷ = 82991303 is a prime.

It is a super-2 number, since 2×82991431² = 13775155238855522, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (82998431) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 41495715 + 41495716.

It is an arithmetic number, because the mean of its divisors is an integer number (41495716).

Almost surely, 2^82991431 is an apocalyptic number.

82991431 is a deficient number, since it is larger than the sum of its proper divisors (1).

82991431 is an equidigital number, since it uses as much as digits as its factorization.

82991431 is an evil number, because the sum of its binary digits is even.

The product of its digits is 15552, while the sum is 37.

The square root of 82991431 is about 9109.9632820336. The cubic root of 82991431 is about 436.1920551495.

It can be divided in two parts, 8299 and 1431, that added together give a triangular number (9730 = T₁₃₉).

The spelling of 82991431 in words is "eighty-two million, nine hundred ninety-one thousand, four hundred thirty-one".