21113131212 has 36 divisors (see below), whose sum is σ = 53420179176. Its totient is φ = 7031001600.

The previous prime is 21113131141. The next prime is 21113131213. The reversal of 21113131212 is 21213131112.

21113131212 is a `hidden beast` number, since 211 + 131 + 312 + 12 = 666.

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a nude number because it is divisible by every one of its digits.

It is not an unprimeable number, because it can be changed into a prime (21113131213) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 241173 + ... + 316844.

It is an arithmetic number, because the mean of its divisors is an integer number (1483893866).

Almost surely, 2^21113131212 is an apocalyptic number.

It is an amenable number.

21113131212 is an abundant number, since it is smaller than the sum of its proper divisors (32307047964).

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

21113131212 is a wasteful number, since it uses less digits than its factorization.

21113131212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 559078 (or 559073 counting only the distinct ones).

The product of its digits is 72, while the sum is 18.

Adding to 21113131212 its reverse (21213131112), we get a palindrome (42326262324).

The spelling of 21113131212 in words is "twenty-one billion, one hundred thirteen million, one hundred thirty-one thousand, two hundred twelve".