18521117028 has 72 divisors (see below), whose sum is σ = 48528736256. Its totient is φ = 5949676800.

The previous prime is 18521116931. The next prime is 18521117081. The reversal of 18521117028 is 82071112581.

18521117028 is a `hidden beast` number, since 18 + 521 + 117 + 0 + 2 + 8 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 18521116983 and 18521117001.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 234525 + ... + 303387.

Almost surely, 2^18521117028 is an apocalyptic number.

18521117028 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18521117028, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24264368128).

18521117028 is an abundant number, since it is smaller than the sum of its proper divisors (30007619228).

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

18521117028 is a wasteful number, since it uses less digits than its factorization.

18521117028 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 69145 (or 69140 counting only the distinct ones).

The product of its (nonzero) digits is 8960, while the sum is 36.

The spelling of 18521117028 in words is "eighteen billion, five hundred twenty-one million, one hundred seventeen thousand, twenty-eight".