21001925880 has 576 divisors, whose sum is σ = 80281393920. Its totient is φ = 4727808000.

The previous prime is 21001925839. The next prime is 21001925881. The reversal of 21001925880 is 8852910012.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21001925881) by changing a digit.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 52373680 + ... + 52374080.

It is an arithmetic number, because the mean of its divisors is an integer number (139377420).

Almost surely, 2^21001925880 is an apocalyptic number.

21001925880 is a gapful number since it is divisible by the number (20) 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 21001925880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40140696960).

21001925880 is an abundant number, since it is smaller than the sum of its proper divisors (59279468040).

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

21001925880 is a wasteful number, since it uses less digits than its factorization.

21001925880 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 500 (or 474 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 36.

The spelling of 21001925880 in words is "twenty-one billion, one million, nine hundred twenty-five thousand, eight hundred eighty".