81156871 has 2 divisors, whose sum is σ = 81156872. Its totient is φ = 81156870.

The previous prime is 81156851. The next prime is 81156883. The reversal of 81156871 is 17865118.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81156871 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81156871.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81156821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40578435 + 40578436.

It is an arithmetic number, because the mean of its divisors is an integer number (40578436).

Almost surely, 2^81156871 is an apocalyptic number.

81156871 is a deficient number, since it is larger than the sum of its proper divisors (1).

81156871 is an equidigital number, since it uses as much as digits as its factorization.

81156871 is an evil number, because the sum of its binary digits is even.

The product of its digits is 13440, while the sum is 37.

The square root of 81156871 is about 9008.7108400703. The cubic root of 81156871 is about 432.9540084172.

The spelling of 81156871 in words is "eighty-one million, one hundred fifty-six thousand, eight hundred seventy-one".