21202101220 has 24 divisors (see below), whose sum is σ = 45610375608. Its totient is φ = 8273990400.

The previous prime is 21202101199. The next prime is 21202101227. The reversal of 21202101220 is 2210120212.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 2573127076 + 18628974144 = 50726^2 + 136488^2 .

It is a super-2 number, since 2×21202101220² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21202101220.

It is not an unprimeable number, because it can be changed into a prime (21202101227) 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, 12927291 + ... + 12928930.

It is an arithmetic number, because the mean of its divisors is an integer number (1900432317).

Almost surely, 2^21202101220 is an apocalyptic number.

21202101220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21202101220 is an abundant number, since it is smaller than the sum of its proper divisors (24408274388).

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

21202101220 is a wasteful number, since it uses less digits than its factorization.

21202101220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25856271 (or 25856269 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 13.

Adding to 21202101220 its reverse (2210120212), we get a palindrome (23412221432).

The spelling of 21202101220 in words is "twenty-one billion, two hundred two million, one hundred one thousand, two hundred twenty".