21211202020 has 24 divisors (see below), whose sum is σ = 44716856184. Its totient is φ = 8451465216.

The previous prime is 21211201987. The next prime is 21211202099. The reversal of 21211202020 is 2020211212.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 12246520896 + 8964681124 = 110664^2 + 94682^2 .

It is a super-2 number, since 2×21211202020² (a number of 21 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2058207 + ... + 2068486.

It is an arithmetic number, because the mean of its divisors is an integer number (1863202341).

Almost surely, 2^21211202020 is an apocalyptic number.

21211202020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21211202020 is an abundant number, since it is smaller than the sum of its proper divisors (23505654164).

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

21211202020 is a wasteful number, since it uses less digits than its factorization.

21211202020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4126959 (or 4126957 counting only the distinct ones).

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

Adding to 21211202020 its reverse (2020211212), we get a palindrome (23231413232).

The spelling of 21211202020 in words is "twenty-one billion, two hundred eleven million, two hundred two thousand, twenty".