81791767 has 2 divisors, whose sum is σ = 81791768. Its totient is φ = 81791766.

The previous prime is 81791737. The next prime is 81791771. The reversal of 81791767 is 76719718.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81791767 - 2⁷ = 81791639 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81791737) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40895883 + 40895884.

It is an arithmetic number, because the mean of its divisors is an integer number (40895884).

Almost surely, 2^81791767 is an apocalyptic number.

81791767 is a deficient number, since it is larger than the sum of its proper divisors (1).

81791767 is an equidigital number, since it uses as much as digits as its factorization.

81791767 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 148176, while the sum is 46.

The square root of 81791767 is about 9043.8800854500. The cubic root of 81791767 is about 434.0800870843.

The spelling of 81791767 in words is "eighty-one million, seven hundred ninety-one thousand, seven hundred sixty-seven".