18211031 has 4 divisors (see below), whose sum is σ = 18279000. Its totient is φ = 18143064.

The previous prime is 18211021. The next prime is 18211033. The reversal of 18211031 is 13011281.

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 18211031 - 2²² = 14016727 is a prime.

It is a super-2 number, since 2×18211031² = 663283300165922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18211033) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 33581 + ... + 34118.

It is an arithmetic number, because the mean of its divisors is an integer number (4569750).

Almost surely, 2^18211031 is an apocalyptic number.

18211031 is a deficient number, since it is larger than the sum of its proper divisors (67969).

18211031 is an equidigital number, since it uses as much as digits as its factorization.

18211031 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 67968.

The product of its (nonzero) digits is 48, while the sum is 17.

The square root of 18211031 is about 4267.4384588416. The cubic root of 18211031 is about 263.0943436919.

The spelling of 18211031 in words is "eighteen million, two hundred eleven thousand, thirty-one".