18821945520 has 480 divisors, whose sum is σ = 74030261760. Its totient is φ = 4196966400.

The previous prime is 18821945497. The next prime is 18821945521. The reversal of 18821945520 is 2554912881.

18821945520 is a `hidden beast` number, since 1 + 8 + 8 + 2 + 1 + 94 + 552 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is not an unprimeable number, because it can be changed into a prime (18821945521) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 46937320 + ... + 46937720.

It is an arithmetic number, because the mean of its divisors is an integer number (154229712).

Almost surely, 2^18821945520 is an apocalyptic number.

18821945520 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 18821945520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37015130880).

18821945520 is an abundant number, since it is smaller than the sum of its proper divisors (55208316240).

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

18821945520 is a wasteful number, since it uses less digits than its factorization.

18821945520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 633 (or 624 counting only the distinct ones).

The product of its (nonzero) digits is 230400, while the sum is 45.

The spelling of 18821945520 in words is "eighteen billion, eight hundred twenty-one million, nine hundred forty-five thousand, five hundred twenty".