18214471521 has 9 divisors (see below), whose sum is σ = 26310377041. Its totient is φ = 12142711092.

The previous prime is 18214471447. The next prime is 18214471559. The reversal of 18214471521 is 12517441281.

The square root of 18214471521 is 134961.

It is a perfect power (a square), and thus also a powerful number.

18214471521 is a `hidden beast` number, since 1 + 8 + 21 + 44 + 71 + 521 = 666.

It is a tau number, because it is divible by the number of its divisors (9).

It is not a de Polignac number, because 18214471521 - 2¹⁹ = 18213947233 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18214471571) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 382390 + ... + 427376.

Almost surely, 2^18214471521 is an apocalyptic number.

18214471521 is the 134961-st square number.

18214471521 is the 67481-st centered octagonal number.

It is an amenable number.

18214471521 is a deficient number, since it is larger than the sum of its proper divisors (8095905520).

18214471521 is an frugal number, since it uses more digits than its factorization.

18214471521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 89980 (or 44990 counting only the distinct ones).

The product of its digits is 17920, while the sum is 36.

Multiplying 18214471521 by its sum of digits (36), we get a square (655720974756 = 809766²).

The spelling of 18214471521 in words is "eighteen billion, two hundred fourteen million, four hundred seventy-one thousand, five hundred twenty-one".