21312400212 has 60 divisors (see below), whose sum is σ = 55765649940. Its totient is φ = 7097652864.

The previous prime is 21312400189. The next prime is 21312400247. The reversal of 21312400212 is 21200421312.

It is a happy number.

21312400212 is a `hidden beast` number, since 21 + 31 + 2 + 400 + 212 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 2509408836 + 18802991376 = 50094^2 + 137124^2 .

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 332464 + ... + 391352.

It is an arithmetic number, because the mean of its divisors is an integer number (929427499).

Almost surely, 2^21312400212 is an apocalyptic number.

It is an amenable number.

21312400212 is an abundant number, since it is smaller than the sum of its proper divisors (34453249728).

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

21312400212 is a wasteful number, since it uses less digits than its factorization.

21312400212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 60022 (or 60011 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

Adding to 21312400212 its reverse (21200421312), we get a palindrome (42512821524).

The spelling of 21312400212 in words is "twenty-one billion, three hundred twelve million, four hundred thousand, two hundred twelve".