18210521 has 16 divisors (see below), whose sum is σ = 21753600. Its totient is φ = 14914368.

The previous prime is 18210509. The next prime is 18210539. The reversal of 18210521 is 12501281.

18210521 = T₃₁₈ + T₃₁₉ + ... + T₅₂₀.

It is a happy number.

It is not a de Polignac number, because 18210521 - 2¹⁸ = 17948377 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 18210493 and 18210502.

It is not an unprimeable number, because it can be changed into a prime (18210541) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 21716 + ... + 22538.

It is an arithmetic number, because the mean of its divisors is an integer number (1359600).

Almost surely, 2^18210521 is an apocalyptic number.

It is an amenable number.

18210521 is a deficient number, since it is larger than the sum of its proper divisors (3543079).

18210521 is a wasteful number, since it uses less digits than its factorization.

18210521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 968.

The product of its (nonzero) digits is 160, while the sum is 20.

The square root of 18210521 is about 4267.3787036072. The cubic root of 18210521 is about 263.0918876829.

The spelling of 18210521 in words is "eighteen million, two hundred ten thousand, five hundred twenty-one".