21020620280 has 128 divisors (see below), whose sum is σ = 52822056960. Its totient is φ = 7463040000.

The previous prime is 21020620277. The next prime is 21020620321. The reversal of 21020620280 is 8202602012.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 10773305 + ... + 10775255.

It is an arithmetic number, because the mean of its divisors is an integer number (412672320).

Almost surely, 2^21020620280 is an apocalyptic number.

21020620280 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 21020620280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26411028480).

21020620280 is an abundant number, since it is smaller than the sum of its proper divisors (31801436680).

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

21020620280 is a wasteful number, since it uses less digits than its factorization.

21020620280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2541 (or 2537 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 23.

The spelling of 21020620280 in words is "twenty-one billion, twenty million, six hundred twenty thousand, two hundred eighty".