81147571 has 2 divisors, whose sum is σ = 81147572. Its totient is φ = 81147570.

The previous prime is 81147527. The next prime is 81147587. The reversal of 81147571 is 17574118.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81147571 is a prime.

It is not a weakly prime, because it can be changed into another prime (81147071) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40573785 + 40573786.

It is an arithmetic number, because the mean of its divisors is an integer number (40573786).

Almost surely, 2^81147571 is an apocalyptic number.

81147571 is a deficient number, since it is larger than the sum of its proper divisors (1).

81147571 is an equidigital number, since it uses as much as digits as its factorization.

81147571 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 7840, while the sum is 34.

The square root of 81147571 is about 9008.1946581987. The cubic root of 81147571 is about 432.9374699692.

It can be divided in two parts, 81147 and 571, that added together give a palindrome (81718).

The spelling of 81147571 in words is "eighty-one million, one hundred forty-seven thousand, five hundred seventy-one".