81376931 has 2 divisors, whose sum is σ = 81376932. Its totient is φ = 81376930.

The previous prime is 81376877. The next prime is 81376963. The reversal of 81376931 is 13967318.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81376931 - 2¹⁰ = 81375907 is a prime.

It is a super-3 number, since 3×81376931³ (a number of 25 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (81370931) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40688465 + 40688466.

It is an arithmetic number, because the mean of its divisors is an integer number (40688466).

Almost surely, 2^81376931 is an apocalyptic number.

81376931 is a deficient number, since it is larger than the sum of its proper divisors (1).

81376931 is an equidigital number, since it uses as much as digits as its factorization.

81376931 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 27216, while the sum is 38.

The square root of 81376931 is about 9020.9163060079. The cubic root of 81376931 is about 433.3449791085.

The spelling of 81376931 in words is "eighty-one million, three hundred seventy-six thousand, nine hundred thirty-one".