18154021 has 4 divisors (see below), whose sum is σ = 18596844. Its totient is φ = 17711200.

The previous prime is 18153997. The next prime is 18154033. The reversal of 18154021 is 12045181.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 261121 + 17892900 = 511^2 + 4230^2 .

It is a cyclic number.

It is not a de Polignac number, because 18154021 - 2¹⁵ = 18121253 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 18153983 and 18154001.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18154051) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 221350 + ... + 221431.

It is an arithmetic number, because the mean of its divisors is an integer number (4649211).

Almost surely, 2^18154021 is an apocalyptic number.

It is an amenable number.

18154021 is a deficient number, since it is larger than the sum of its proper divisors (442823).

18154021 is an equidigital number, since it uses as much as digits as its factorization.

18154021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 442822.

The product of its (nonzero) digits is 320, while the sum is 22.

The square root of 18154021 is about 4260.7535718462. The cubic root of 18154021 is about 262.8195159904.

The spelling of 18154021 in words is "eighteen million, one hundred fifty-four thousand, twenty-one".