18813021 has 8 divisors (see below), whose sum is σ = 26404320. Its totient is φ = 11881872.

The previous prime is 18813017. The next prime is 18813023. The reversal of 18813021 is 12031881.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 18813021 - 2² = 18813017 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 18812982 and 18813000.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18813023) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 164970 + ... + 165083.

It is an arithmetic number, because the mean of its divisors is an integer number (3300540).

Almost surely, 2^18813021 is an apocalyptic number.

It is an amenable number.

18813021 is a deficient number, since it is larger than the sum of its proper divisors (7591299).

18813021 is a wasteful number, since it uses less digits than its factorization.

18813021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 330075.

The product of its (nonzero) digits is 384, while the sum is 24.

The square root of 18813021 is about 4337.3979526901. The cubic root of 18813021 is about 265.9619530259.

The spelling of 18813021 in words is "eighteen million, eight hundred thirteen thousand, twenty-one".