21131220412 has 12 divisors (see below), whose sum is σ = 37008467496. Its totient is φ = 10557372560.

The previous prime is 21131220361. The next prime is 21131220413. The reversal of 21131220412 is 21402213112.

It is a super-2 number, since 2×21131220412² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21131220412.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21131220413) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2053639 + ... + 2063902.

It is an arithmetic number, because the mean of its divisors is an integer number (3084038958).

Almost surely, 2^21131220412 is an apocalyptic number.

It is an amenable number.

21131220412 is a deficient number, since it is larger than the sum of its proper divisors (15877247084).

21131220412 is a wasteful number, since it uses less digits than its factorization.

21131220412 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4118828 (or 4118826 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 19.

Adding to 21131220412 its reverse (21402213112), we get a palindrome (42533433524).

The spelling of 21131220412 in words is "twenty-one billion, one hundred thirty-one million, two hundred twenty thousand, four hundred twelve".