81358859 has 2 divisors, whose sum is σ = 81358860. Its totient is φ = 81358858.

The previous prime is 81358777. The next prime is 81358873. The reversal of 81358859 is 95885318.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81358859 - 2⁸ = 81358603 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (81358159) by changing a digit.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40679429 + 40679430.

It is an arithmetic number, because the mean of its divisors is an integer number (40679430).

Almost surely, 2^81358859 is an apocalyptic number.

81358859 is a deficient number, since it is larger than the sum of its proper divisors (1).

81358859 is an equidigital number, since it uses as much as digits as its factorization.

81358859 is an evil number, because the sum of its binary digits is even.

The product of its digits is 345600, while the sum is 47.

The square root of 81358859 is about 9019.9145783095. The cubic root of 81358859 is about 433.3128979844.

The spelling of 81358859 in words is "eighty-one million, three hundred fifty-eight thousand, eight hundred fifty-nine".