81791611 has 16 divisors (see below), whose sum is σ = 93461760. Its totient is φ = 70852320.

The previous prime is 81791581. The next prime is 81791639. The reversal of 81791611 is 11619718.

It is not a de Polignac number, because 81791611 - 2²³ = 73403003 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81791681) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 95461 + ... + 96313.

It is an arithmetic number, because the mean of its divisors is an integer number (5841360).

Almost surely, 2^81791611 is an apocalyptic number.

81791611 is a deficient number, since it is larger than the sum of its proper divisors (11670149).

81791611 is a wasteful number, since it uses less digits than its factorization.

81791611 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1266.

The product of its digits is 3024, while the sum is 34.

The square root of 81791611 is about 9043.8714608292. The cubic root of 81791611 is about 434.0798111130.

The spelling of 81791611 in words is "eighty-one million, seven hundred ninety-one thousand, six hundred eleven".