21371907220 has 24 divisors (see below), whose sum is σ = 44890267464. Its totient is φ = 8546998656.

The previous prime is 21371907203. The next prime is 21371907229. The reversal of 21371907220 is 2270917312.

It can be written as a sum of positive squares in 4 ways, for example, as 9492215184 + 11879692036 = 97428^2 + 108994^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21371907229) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8647 + ... + 206926.

It is an arithmetic number, because the mean of its divisors is an integer number (1870427811).

Almost surely, 2^21371907220 is an apocalyptic number.

21371907220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21371907220 is an abundant number, since it is smaller than the sum of its proper divisors (23518360244).

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

21371907220 is a wasteful number, since it uses less digits than its factorization.

21371907220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 220539 (or 220537 counting only the distinct ones).

The product of its (nonzero) digits is 10584, while the sum is 34.

The spelling of 21371907220 in words is "twenty-one billion, three hundred seventy-one million, nine hundred seven thousand, two hundred twenty".