81856351 has 8 divisors (see below), whose sum is σ = 86252400. Its totient is φ = 77469120.

The previous prime is 81856349. The next prime is 81856361. The reversal of 81856351 is 15365818.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 81856351 - 2¹ = 81856349 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81856351.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81856301) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 26685 + ... + 29593.

It is an arithmetic number, because the mean of its divisors is an integer number (10781550).

Almost surely, 2^81856351 is an apocalyptic number.

81856351 is a deficient number, since it is larger than the sum of its proper divisors (4396049).

81856351 is a wasteful number, since it uses less digits than its factorization.

81856351 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4409.

The product of its digits is 28800, while the sum is 37.

The square root of 81856351 is about 9047.4499722297. The cubic root of 81856351 is about 434.1943090643.

The spelling of 81856351 in words is "eighty-one million, eight hundred fifty-six thousand, three hundred fifty-one".