81051599 has 2 divisors, whose sum is σ = 81051600. Its totient is φ = 81051598.

The previous prime is 81051589. The next prime is 81051601. The reversal of 81051599 is 99515018.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81051599 - 2⁸ = 81051343 is a prime.

Together with 81051601, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81051539) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40525799 + 40525800.

It is an arithmetic number, because the mean of its divisors is an integer number (40525800).

Almost surely, 2^81051599 is an apocalyptic number.

81051599 is a deficient number, since it is larger than the sum of its proper divisors (1).

81051599 is an equidigital number, since it uses as much as digits as its factorization.

81051599 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 16200, while the sum is 38.

The square root of 81051599 is about 9002.8661547309. The cubic root of 81051599 is about 432.7667264490.

The spelling of 81051599 in words is "eighty-one million, fifty-one thousand, five hundred ninety-nine".