18521019520 has 32 divisors (see below), whose sum is σ = 44276813820. Its totient is φ = 7408407552.

The previous prime is 18521019511. The next prime is 18521019523. The reversal of 18521019520 is 2591012581.

It can be written as a sum of positive squares in 2 ways, for example, as 18511235136 + 9784384 = 136056^2 + 3128^2 .

It is a tau number, because it is divible by the number of its divisors (32).

It is not an unprimeable number, because it can be changed into a prime (18521019523) 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, 14468907 + ... + 14470186.

Almost surely, 2^18521019520 is an apocalyptic number.

18521019520 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18521019520 is an abundant number, since it is smaller than the sum of its proper divisors (25755794300).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

18521019520 is an equidigital number, since it uses as much as digits as its factorization.

18521019520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28939112 (or 28939100 counting only the distinct ones).

The product of its (nonzero) digits is 7200, while the sum is 34.

The spelling of 18521019520 in words is "eighteen billion, five hundred twenty-one million, nineteen thousand, five hundred twenty".