21002222020 has 48 divisors (see below), whose sum is σ = 48393540720. Its totient is φ = 7608347136.

The previous prime is 21002222011. The next prime is 21002222089. The reversal of 21002222020 is 2022220012.

It can be written as a sum of positive squares in 8 ways, for example, as 744962436 + 20257259584 = 27294^2 + 142328^2 .

It is a Harshad number since it is a multiple of its sum of digits (13).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 748275 + ... + 775834.

It is an arithmetic number, because the mean of its divisors is an integer number (1008198765).

Almost surely, 2^21002222020 is an apocalyptic number.

21002222020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21002222020 is an abundant number, since it is smaller than the sum of its proper divisors (27391318700).

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

21002222020 is a wasteful number, since it uses less digits than its factorization.

21002222020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1524184 (or 1524182 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 13.

Adding to 21002222020 its reverse (2022220012), we get a palindrome (23024442032).

The spelling of 21002222020 in words is "twenty-one billion, two million, two hundred twenty-two thousand, twenty".