81992951 has 2 divisors, whose sum is σ = 81992952. Its totient is φ = 81992950.

The previous prime is 81992929. The next prime is 81992971. The reversal of 81992951 is 15929918.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81992951 - 2¹⁸ = 81730807 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81992971) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40996475 + 40996476.

It is an arithmetic number, because the mean of its divisors is an integer number (40996476).

Almost surely, 2^81992951 is an apocalyptic number.

81992951 is a deficient number, since it is larger than the sum of its proper divisors (1).

81992951 is an equidigital number, since it uses as much as digits as its factorization.

81992951 is an evil number, because the sum of its binary digits is even.

The product of its digits is 58320, while the sum is 44.

The square root of 81992951 is about 9054.9959138588. The cubic root of 81992951 is about 434.4356993380.

The spelling of 81992951 in words is "eighty-one million, nine hundred ninety-two thousand, nine hundred fifty-one".