18072021 has 48 divisors (see below), whose sum is σ = 29187648. Its totient is φ = 9849600.

The previous prime is 18072011. The next prime is 18072023. The reversal of 18072021 is 12027081.

It is not a de Polignac number, because 18072021 - 2⁶ = 18071957 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18072023) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 440761 + ... + 440801.

It is an arithmetic number, because the mean of its divisors is an integer number (608076).

Almost surely, 2^18072021 is an apocalyptic number.

18072021 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

18072021 is a deficient number, since it is larger than the sum of its proper divisors (11115627).

18072021 is a wasteful number, since it uses less digits than its factorization.

18072021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 130 (or 111 counting only the distinct ones).

The product of its (nonzero) digits is 224, while the sum is 21.

The square root of 18072021 is about 4251.1199700785. The cubic root of 18072021 is about 262.4232083766.

It can be divided in two parts, 1807 and 2021, that added together give a triangular number (3828 = T₈₇).

The spelling of 18072021 in words is "eighteen million, seventy-two thousand, twenty-one".