81159031 has 2 divisors, whose sum is σ = 81159032. Its totient is φ = 81159030.

The previous prime is 81159007. The next prime is 81159077. The reversal of 81159031 is 13095118.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81159031 - 2⁵ = 81158999 is a prime.

It is a super-2 number, since 2×81159031² = 13173576625717922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81159931) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40579515 + 40579516.

It is an arithmetic number, because the mean of its divisors is an integer number (40579516).

Almost surely, 2^81159031 is an apocalyptic number.

81159031 is a deficient number, since it is larger than the sum of its proper divisors (1).

81159031 is an equidigital number, since it uses as much as digits as its factorization.

81159031 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1080, while the sum is 28.

The square root of 81159031 is about 9008.8307232404. The cubic root of 81159031 is about 432.9578494244.

The spelling of 81159031 in words is "eighty-one million, one hundred fifty-nine thousand, thirty-one".