18488021 has 6 divisors (see below), whose sum is σ = 19327350. Its totient is φ = 17683688.

The previous prime is 18488011. The next prime is 18488023. The reversal of 18488021 is 12088481.

It can be written as a sum of positive squares in only one way, i.e., 11122225 + 7365796 = 3335^2 + 2714^2 .

It is not a de Polignac number, because 18488021 - 2¹⁰ = 18486997 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18488023) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 16946 + ... + 18003.

It is an arithmetic number, because the mean of its divisors is an integer number (3221225).

Almost surely, 2^18488021 is an apocalyptic number.

It is an amenable number.

18488021 is a deficient number, since it is larger than the sum of its proper divisors (839329).

18488021 is an equidigital number, since it uses as much as digits as its factorization.

18488021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34995 (or 34972 counting only the distinct ones).

The product of its (nonzero) digits is 4096, while the sum is 32.

The square root of 18488021 is about 4299.7698775632. The cubic root of 18488021 is about 264.4215268150.

The spelling of 18488021 in words is "eighteen million, four hundred eighty-eight thousand, twenty-one".