18039431 has 4 divisors (see below), whose sum is σ = 19100592. Its totient is φ = 16978272.

The previous prime is 18039419. The next prime is 18039443. The reversal of 18039431 is 13493081.

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

It is an interprime number because it is at equal distance from previous prime (18039419) and next prime (18039443).

It is a cyclic number.

It is not a de Polignac number, because 18039431 - 2⁶ = 18039367 is a prime.

It is a super-2 number, since 2×18039431² = 650842141607522, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 18039394 and 18039403.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18039401) 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, 530555 + ... + 530588.

It is an arithmetic number, because the mean of its divisors is an integer number (4775148).

Almost surely, 2^18039431 is an apocalyptic number.

18039431 is a deficient number, since it is larger than the sum of its proper divisors (1061161).

18039431 is a wasteful number, since it uses less digits than its factorization.

18039431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1061160.

The product of its (nonzero) digits is 2592, while the sum is 29.

The square root of 18039431 is about 4247.2851328819. The cubic root of 18039431 is about 262.2653673607.

The spelling of 18039431 in words is "eighteen million, thirty-nine thousand, four hundred thirty-one".