18231021 has 16 divisors (see below), whose sum is σ = 28598400. Its totient is φ = 11438784.

The previous prime is 18230969. The next prime is 18231029. The reversal of 18231021 is 12013281.

It is not a de Polignac number, because 18231021 - 2⁶ = 18230957 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 18230985 and 18231003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18231029) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 19401 + ... + 20318.

It is an arithmetic number, because the mean of its divisors is an integer number (1787400).

Almost surely, 2^18231021 is an apocalyptic number.

It is an amenable number.

18231021 is a deficient number, since it is larger than the sum of its proper divisors (10367379).

18231021 is a wasteful number, since it uses less digits than its factorization.

18231021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39745 (or 39739 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 18.

The square root of 18231021 is about 4269.7799709119. The cubic root of 18231021 is about 263.1905735130.

The spelling of 18231021 in words is "eighteen million, two hundred thirty-one thousand, twenty-one".