81356311 has 4 divisors (see below), whose sum is σ = 81512392. Its totient is φ = 81200232.

The previous prime is 81356293. The next prime is 81356321. The reversal of 81356311 is 11365318.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 11365318 = 2 ⋅5682659.

It is a cyclic number.

It is not a de Polignac number, because 81356311 - 2⁵ = 81356279 is a prime.

It is a deceptive number, since it divides R_81356310.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 81356311.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81356321) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 77256 + ... + 78301.

It is an arithmetic number, because the mean of its divisors is an integer number (20378098).

Almost surely, 2^81356311 is an apocalyptic number.

81356311 is a deficient number, since it is larger than the sum of its proper divisors (156081).

81356311 is a wasteful number, since it uses less digits than its factorization.

81356311 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 156080.

The product of its digits is 2160, while the sum is 28.

The square root of 81356311 is about 9019.7733341809. The cubic root of 81356311 is about 433.3083744336.

The spelling of 81356311 in words is "eighty-one million, three hundred fifty-six thousand, three hundred eleven".