81588791 has 2 divisors, whose sum is σ = 81588792. Its totient is φ = 81588790.

The previous prime is 81588779. The next prime is 81588823. The reversal of 81588791 is 19788518.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81588791 - 2¹⁸ = 81326647 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81588701) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40794395 + 40794396.

It is an arithmetic number, because the mean of its divisors is an integer number (40794396).

Almost surely, 2^81588791 is an apocalyptic number.

81588791 is a deficient number, since it is larger than the sum of its proper divisors (1).

81588791 is an equidigital number, since it uses as much as digits as its factorization.

81588791 is an evil number, because the sum of its binary digits is even.

The product of its digits is 161280, while the sum is 47.

The square root of 81588791 is about 9032.6513826229. The cubic root of 81588791 is about 433.7207158541.

The spelling of 81588791 in words is "eighty-one million, five hundred eighty-eight thousand, seven hundred ninety-one".