18572021 has 8 divisors (see below), whose sum is σ = 20038200. Its totient is φ = 17111232.

The previous prime is 18572011. The next prime is 18572077. The reversal of 18572021 is 12027581.

It can be written as a sum of positive squares in 4 ways, for example, as 7349521 + 11222500 = 2711^2 + 3350^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 18572021 - 2⁶ = 18571957 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18572011) 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, 8555 + ... + 10503.

It is an arithmetic number, because the mean of its divisors is an integer number (2504775).

Almost surely, 2^18572021 is an apocalyptic number.

It is an amenable number.

18572021 is a deficient number, since it is larger than the sum of its proper divisors (1466179).

18572021 is a wasteful number, since it uses less digits than its factorization.

18572021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2695.

The product of its (nonzero) digits is 1120, while the sum is 26.

The square root of 18572021 is about 4309.5267721642. The cubic root of 18572021 is about 264.8213867001.

The spelling of 18572021 in words is "eighteen million, five hundred seventy-two thousand, twenty-one".