18213969 has 4 divisors (see below), whose sum is σ = 24285296. Its totient is φ = 12142644.

The previous prime is 18213967. The next prime is 18213977. The reversal of 18213969 is 96931281.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 18213969 - 2¹ = 18213967 is a prime.

It is a super-2 number, since 2×18213969² = 663497333465922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18213967) 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, 3035659 + ... + 3035664.

It is an arithmetic number, because the mean of its divisors is an integer number (6071324).

Almost surely, 2^18213969 is an apocalyptic number.

It is an amenable number.

18213969 is a deficient number, since it is larger than the sum of its proper divisors (6071327).

18213969 is an equidigital number, since it uses as much as digits as its factorization.

18213969 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6071326.

The product of its digits is 23328, while the sum is 39.

The square root of 18213969 is about 4267.7826795656. The cubic root of 18213969 is about 263.1084913372.

It can be divided in two parts, 182139 and 69, that multiplied together give a triangular number (12567591 = T₅₀₁₃).

The spelling of 18213969 in words is "eighteen million, two hundred thirteen thousand, nine hundred sixty-nine".