18312891 has 16 divisors (see below), whose sum is σ = 25946400. Its totient is φ = 11467008.

The previous prime is 18312881. The next prime is 18312919. The reversal of 18312891 is 19821381.

It is not a de Polignac number, because 18312891 - 2¹⁴ = 18296507 is a prime.

It is not an unprimeable number, because it can be changed into a prime (18312821) 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, 375 + ... + 6063.

It is an arithmetic number, because the mean of its divisors is an integer number (1621650).

Almost surely, 2^18312891 is an apocalyptic number.

18312891 is a deficient number, since it is larger than the sum of its proper divisors (7633509).

18312891 is a wasteful number, since it uses less digits than its factorization.

18312891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5758.

The product of its digits is 3456, while the sum is 33.

The square root of 18312891 is about 4279.3563768399. The cubic root of 18312891 is about 263.5839549951.

The spelling of 18312891 in words is "eighteen million, three hundred twelve thousand, eight hundred ninety-one".