18640521900 has 1440 divisors, whose sum is σ = 86106155520. Its totient is φ = 3387225600.

The previous prime is 18640521877. The next prime is 18640521917. The reversal of 18640521900 is 912504681.

18640521900 is a `hidden beast` number, since 1 + 8 + 6 + 40 + 521 + 90 + 0 = 666.

It is a super-2 number, since 2×18640521900² (a number of 21 digits) contains 22 as substring.

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

It is an unprimeable number.

It is a polite number, since it can be written in 479 ways as a sum of consecutive naturals, for example, 981080091 + ... + 981080109.

Almost surely, 2^18640521900 is an apocalyptic number.

18640521900 is a gapful number since it is divisible by the number (10) 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 18640521900, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43053077760).

18640521900 is an abundant number, since it is smaller than the sum of its proper divisors (67465633620).

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

18640521900 is a wasteful number, since it uses less digits than its factorization.

18640521900 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 98 (or 60 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 36.

The spelling of 18640521900 in words is "eighteen billion, six hundred forty million, five hundred twenty-one thousand, nine hundred".