21010252220 has 12 divisors (see below), whose sum is σ = 44121529704. Its totient is φ = 8404100880.

The previous prime is 21010252187. The next prime is 21010252229. The reversal of 21010252220 is 2225201012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21010252229) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 525256286 + ... + 525256325.

It is an arithmetic number, because the mean of its divisors is an integer number (3676794142).

Almost surely, 2^21010252220 is an apocalyptic number.

21010252220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21010252220 is an abundant number, since it is smaller than the sum of its proper divisors (23111277484).

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

21010252220 is a wasteful number, since it uses less digits than its factorization.

21010252220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1050512620 (or 1050512618 counting only the distinct ones).

The product of its (nonzero) digits is 160, while the sum is 17.

Adding to 21010252220 its reverse (2225201012), we get a palindrome (23235453232).

The spelling of 21010252220 in words is "twenty-one billion, ten million, two hundred fifty-two thousand, two hundred twenty".