81397311 has 16 divisors (see below), whose sum is σ = 115856640. Its totient is φ = 50682240.

The previous prime is 81397249. The next prime is 81397319. The reversal of 81397311 is 11379318.

It is not a de Polignac number, because 81397311 - 2⁶ = 81397247 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81397319) 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, 6010 + ... + 14103.

It is an arithmetic number, because the mean of its divisors is an integer number (7241040).

Almost surely, 2^81397311 is an apocalyptic number.

81397311 is a deficient number, since it is larger than the sum of its proper divisors (34459329).

81397311 is a wasteful number, since it uses less digits than its factorization.

81397311 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20206.

The product of its digits is 4536, while the sum is 33.

The square root of 81397311 is about 9022.0458322932. The cubic root of 81397311 is about 433.3811516593.

The spelling of 81397311 in words is "eighty-one million, three hundred ninety-seven thousand, three hundred eleven".