82801991 has 2 divisors, whose sum is σ = 82801992. Its totient is φ = 82801990.

The previous prime is 82801987. The next prime is 82802003. The reversal of 82801991 is 19910828.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 82801991 - 2² = 82801987 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (84801991) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 41400995 + 41400996.

It is an arithmetic number, because the mean of its divisors is an integer number (41400996).

Almost surely, 2^82801991 is an apocalyptic number.

82801991 is a deficient number, since it is larger than the sum of its proper divisors (1).

82801991 is an equidigital number, since it uses as much as digits as its factorization.

82801991 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 10368, while the sum is 38.

The square root of 82801991 is about 9099.5599344144. The cubic root of 82801991 is about 435.8599117176.

The spelling of 82801991 in words is "eighty-two million, eight hundred one thousand, nine hundred ninety-one".