21437121312 has 192 divisors, whose sum is σ = 66313416960. Its totient is φ = 6714150912.

The previous prime is 21437121289. The next prime is 21437121313. The reversal of 21437121312 is 21312173412.

21437121312 is a `hidden beast` number, since 2 + 1 + 437 + 1 + 213 + 12 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (21437121313) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 15612658 + ... + 15614030.

It is an arithmetic number, because the mean of its divisors is an integer number (345382380).

Almost surely, 2^21437121312 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 21437121312, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33156708480).

21437121312 is an abundant number, since it is smaller than the sum of its proper divisors (44876295648).

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

21437121312 is a wasteful number, since it uses less digits than its factorization.

21437121312 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2472 (or 2458 counting only the distinct ones).

The product of its digits is 2016, while the sum is 27.

Adding to 21437121312 its reverse (21312173412), we get a palindrome (42749294724).

The spelling of 21437121312 in words is "twenty-one billion, four hundred thirty-seven million, one hundred twenty-one thousand, three hundred twelve".