81590851 has 4 divisors (see below), whose sum is σ = 81618304. Its totient is φ = 81563400.

The previous prime is 81590849. The next prime is 81590863. The reversal of 81590851 is 15809518.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 81590851 - 2¹ = 81590849 is a prime.

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 81590851.

It is not an unprimeable number, because it can be changed into a prime (81590051) 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, 8640 + ... + 15421.

It is an arithmetic number, because the mean of its divisors is an integer number (20404576).

Almost surely, 2^81590851 is an apocalyptic number.

81590851 is a deficient number, since it is larger than the sum of its proper divisors (27453).

81590851 is a wasteful number, since it uses less digits than its factorization.

81590851 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27452.

The product of its (nonzero) digits is 14400, while the sum is 37.

The square root of 81590851 is about 9032.7654126519. The cubic root of 81590851 is about 433.7243660988.

The spelling of 81590851 in words is "eighty-one million, five hundred ninety thousand, eight hundred fifty-one".