21123312312 has 32 divisors (see below), whose sum is σ = 52826910480. Its totient is φ = 7038620160.

The previous prime is 21123312293. The next prime is 21123312317. The reversal of 21123312312 is 21321332112.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21123312317) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 85153 + ... + 222480.

Almost surely, 2^21123312312 is an apocalyptic number.

It is an amenable number.

21123312312 is an abundant number, since it is smaller than the sum of its proper divisors (31703598168).

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

21123312312 is a wasteful number, since it uses less digits than its factorization.

21123312312 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 310503 (or 310499 counting only the distinct ones).

The product of its digits is 432, while the sum is 21.

Adding to 21123312312 its reverse (21321332112), we get a palindrome (42444644424).

The spelling of 21123312312 in words is "twenty-one billion, one hundred twenty-three million, three hundred twelve thousand, three hundred twelve".