21214637544 has 64 divisors (see below), whose sum is σ = 54375935040. Its totient is φ = 6893258240.

The previous prime is 21214637539. The next prime is 21214637551. The reversal of 21214637544 is 44573641212.

It is a super-2 number, since 2×21214637544² (a number of 21 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1248127 + ... + 1265009.

It is an arithmetic number, because the mean of its divisors is an integer number (849623985).

Almost surely, 2^21214637544 is an apocalyptic number.

21214637544 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21214637544, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27187967520).

21214637544 is an abundant number, since it is smaller than the sum of its proper divisors (33161297496).

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

21214637544 is a wasteful number, since it uses less digits than its factorization.

21214637544 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18210 (or 18206 counting only the distinct ones).

The product of its digits is 161280, while the sum is 39.

The spelling of 21214637544 in words is "twenty-one billion, two hundred fourteen million, six hundred thirty-seven thousand, five hundred forty-four".