21080851020 has 360 divisors, whose sum is σ = 73248858144. Its totient is φ = 5057344512.

The previous prime is 21080851019. The next prime is 21080851049. The reversal of 21080851020 is 2015808012.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a polite number, since it can be written in 119 ways as a sum of consecutive naturals, for example, 14567937 + ... + 14569383.

Almost surely, 2^21080851020 is an apocalyptic number.

21080851020 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 21080851020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36624429072).

21080851020 is an abundant number, since it is smaller than the sum of its proper divisors (52168007124).

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

21080851020 is a wasteful number, since it uses less digits than its factorization.

21080851020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1531 (or 1497 counting only the distinct ones).

The product of its (nonzero) digits is 1280, while the sum is 27.

The spelling of 21080851020 in words is "twenty-one billion, eighty million, eight hundred fifty-one thousand, twenty".