76991 has 2 divisors, whose sum is σ = 76992. Its totient is φ = 76990.

The previous prime is 76963. The next prime is 77003. The reversal of 76991 is 19967.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 76991 - 2¹⁰ = 75967 is a prime.

It is a super-2 number, since 2×76991² = 11855228162, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (76961) 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, 38495 + 38496.

It is an arithmetic number, because the mean of its divisors is an integer number (38496).

2⁷⁶⁹⁹¹ is an apocalyptic number.

76991 is a deficient number, since it is larger than the sum of its proper divisors (1).

76991 is an equidigital number, since it uses as much as digits as its factorization.

76991 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3402, while the sum is 32.

The square root of 76991 is about 277.4725211620. The cubic root of 76991 is about 42.5415510590.

The spelling of 76991 in words is "seventy-six thousand, nine hundred ninety-one".