21020211212 has 72 divisors (see below), whose sum is σ = 49661644032. Its totient is φ = 7559697600.

The previous prime is 21020211209. The next prime is 21020211269. The reversal of 21020211212 is 21211202012.

It is a Harshad number since it is a multiple of its sum of digits (14).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 149864 + ... + 253967.

It is an arithmetic number, because the mean of its divisors is an integer number (689745056).

Almost surely, 2^21020211212 is an apocalyptic number.

21020211212 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

21020211212 is an abundant number, since it is smaller than the sum of its proper divisors (28641432820).

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

21020211212 is a wasteful number, since it uses less digits than its factorization.

21020211212 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 403879 (or 403864 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 21020211212 its reverse (21211202012), we get a palindrome (42231413224).

It can be divided in two parts, 21020 and 211212, that added together give a palindrome (232232).

The spelling of 21020211212 in words is "twenty-one billion, twenty million, two hundred eleven thousand, two hundred twelve".