21204240212 has 54 divisors (see below), whose sum is σ = 38614408938. Its totient is φ = 10184698368.

The previous prime is 21204240203. The next prime is 21204240221.

21204240212 is nontrivially palindromic in base 10.

It is an interprime number because it is at equal distance from previous prime (21204240203) and next prime (21204240221).

It can be written as a sum of positive squares in 9 ways, for example, as 317053636 + 20887186576 = 17806^2 + 144524^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 154775408 + ... + 154775544.

It is an arithmetic number, because the mean of its divisors is an integer number (715081647).

Almost surely, 2^21204240212 is an apocalyptic number.

It is an amenable number.

21204240212 is a deficient number, since it is larger than the sum of its proper divisors (17410168726).

21204240212 is an equidigital number, since it uses as much as digits as its factorization.

21204240212 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 477 (or 265 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 20.

The spelling of 21204240212 in words is "twenty-one billion, two hundred four million, two hundred forty thousand, two hundred twelve".