21263836212 has 72 divisors (see below), whose sum is σ = 55823531400. Its totient is φ = 6818853888.

The previous prime is 21263836193. The next prime is 21263836241.

21263836212 is a `hidden beast` number, since 2 + 1 + 2 + 638 + 3 + 6 + 2 + 12 = 666.

21263836212 is nontrivially palindromic in base 10.

It can be written as a sum of positive squares in 4 ways, for example, as 3069603216 + 18194232996 = 55404^2 + 134886^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

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, 28864 + ... + 208232.

It is an arithmetic number, because the mean of its divisors is an integer number (775326825).

Almost surely, 2^21263836212 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21263836212, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27911765700).

21263836212 is an abundant number, since it is smaller than the sum of its proper divisors (34559695188).

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

21263836212 is a wasteful number, since it uses less digits than its factorization.

21263836212 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 179505 (or 179500 counting only the distinct ones).

The product of its digits is 41472, while the sum is 36.

The spelling of 21263836212 in words is "twenty-one billion, two hundred sixty-three million, eight hundred thirty-six thousand, two hundred twelve".