18211257 has 16 divisors (see below), whose sum is σ = 27639360. Its totient is φ = 11844000.

The previous prime is 18211243. The next prime is 18211283. The reversal of 18211257 is 75211281.

It is not a de Polignac number, because 18211257 - 2⁴ = 18211241 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a self number, because there is not a number n which added to its sum of digits gives 18211257.

It is not an unprimeable number, because it can be changed into a prime (18211057) 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 15 ways as a sum of consecutive naturals, for example, 7119 + ... + 9332.

It is an arithmetic number, because the mean of its divisors is an integer number (1727460).

Almost surely, 2^18211257 is an apocalyptic number.

It is an amenable number.

18211257 is a deficient number, since it is larger than the sum of its proper divisors (9428103).

18211257 is a wasteful number, since it uses less digits than its factorization.

18211257 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16501 (or 16495 counting only the distinct ones).

The product of its digits is 1120, while the sum is 27.

The square root of 18211257 is about 4267.4649383445. The cubic root of 18211257 is about 263.0954320264.

The spelling of 18211257 in words is "eighteen million, two hundred eleven thousand, two hundred fifty-seven".