18501021 has 48 divisors (see below), whose sum is σ = 34473600. Its totient is φ = 9599040.

The previous prime is 18501011. The next prime is 18501023. The reversal of 18501021 is 12010581.

It is not a de Polignac number, because 18501021 - 2¹⁵ = 18468253 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 18500985 and 18501003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18501023) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 22465 + ... + 23273.

It is an arithmetic number, because the mean of its divisors is an integer number (718200).

Almost surely, 2^18501021 is an apocalyptic number.

18501021 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

18501021 is a deficient number, since it is larger than the sum of its proper divisors (15972579).

18501021 is a wasteful number, since it uses less digits than its factorization.

18501021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 847 (or 830 counting only the distinct ones).

The product of its (nonzero) digits is 80, while the sum is 18.

The square root of 18501021 is about 4301.2813207229. The cubic root of 18501021 is about 264.4834889988.

The spelling of 18501021 in words is "eighteen million, five hundred one thousand, twenty-one".