81396679 has 16 divisors (see below), whose sum is σ = 101561152. Its totient is φ = 63514368.

The previous prime is 81396671. The next prime is 81396691. The reversal of 81396679 is 97669318.

It is a cyclic number.

It is not a de Polignac number, because 81396679 - 2³ = 81396671 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81396671) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 517 + ... + 12769.

It is an arithmetic number, because the mean of its divisors is an integer number (6347572).

Almost surely, 2^81396679 is an apocalyptic number.

81396679 is a deficient number, since it is larger than the sum of its proper divisors (20164473).

81396679 is a wasteful number, since it uses less digits than its factorization.

81396679 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12346.

The product of its digits is 489888, while the sum is 49.

The square root of 81396679 is about 9022.0108069100. The cubic root of 81396679 is about 433.3800300104.

The spelling of 81396679 in words is "eighty-one million, three hundred ninety-six thousand, six hundred seventy-nine".