82405991 has 2 divisors, whose sum is σ = 82405992. Its totient is φ = 82405990.

The previous prime is 82405979. The next prime is 82406057. The reversal of 82405991 is 19950428.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-82405991 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (82405091) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 41202995 + 41202996.

It is an arithmetic number, because the mean of its divisors is an integer number (41202996).

Almost surely, 2^82405991 is an apocalyptic number.

82405991 is a deficient number, since it is larger than the sum of its proper divisors (1).

82405991 is an equidigital number, since it uses as much as digits as its factorization.

82405991 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 25920, while the sum is 38.

The square root of 82405991 is about 9077.7745620829. The cubic root of 82405991 is about 435.1639686612.

The spelling of 82405991 in words is "eighty-two million, four hundred five thousand, nine hundred ninety-one".