18020731 has 4 divisors (see below), whose sum is σ = 19080792. Its totient is φ = 16960672.

The previous prime is 18020701. The next prime is 18020747. The reversal of 18020731 is 13702081.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 13702081 = 2683 ⋅5107.

It is a cyclic number.

It is not a de Polignac number, because 18020731 - 2⁵ = 18020699 is a prime.

It is a super-2 number, since 2×18020731² = 649493491548722, which contains 22 as substring.

It is a Smith number, since the sum of its digits (22) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18020701) 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, 530005 + ... + 530038.

It is an arithmetic number, because the mean of its divisors is an integer number (4770198).

Almost surely, 2^18020731 is an apocalyptic number.

18020731 is a deficient number, since it is larger than the sum of its proper divisors (1060061).

18020731 is a wasteful number, since it uses less digits than its factorization.

18020731 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1060060.

The product of its (nonzero) digits is 336, while the sum is 22.

The square root of 18020731 is about 4245.0831558404. The cubic root of 18020731 is about 262.1747130232.

The spelling of 18020731 in words is "eighteen million, twenty thousand, seven hundred thirty-one".