18732021 has 32 divisors (see below), whose sum is σ = 31546368. Its totient is φ = 9603840.

The previous prime is 18732017. The next prime is 18732023. The reversal of 18732021 is 12023781.

It is not a de Polignac number, because 18732021 - 2² = 18732017 is a prime.

It is a super-3 number, since 3×18732021³ (a number of 23 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a junction number, because it is equal to n+sod(n) for n = 18731982 and 18732000.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18732023) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 18685 + ... + 19661.

It is an arithmetic number, because the mean of its divisors is an integer number (985824).

Almost surely, 2^18732021 is an apocalyptic number.

18732021 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

18732021 is a deficient number, since it is larger than the sum of its proper divisors (12814347).

18732021 is a wasteful number, since it uses less digits than its factorization.

18732021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1081.

The product of its (nonzero) digits is 672, while the sum is 24.

The square root of 18732021 is about 4328.0504849181. The cubic root of 18732021 is about 265.5797016365.

The spelling of 18732021 in words is "eighteen million, seven hundred thirty-two thousand, twenty-one".