21231422544 has 80 divisors (see below), whose sum is σ = 57291011712. Its totient is φ = 6762522624.

The previous prime is 21231422543. The next prime is 21231422557. The reversal of 21231422544 is 44522413212.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21231422543) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1131124 + ... + 1149740.

Almost surely, 2^21231422544 is an apocalyptic number.

21231422544 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 21231422544, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28645505856).

21231422544 is an abundant number, since it is smaller than the sum of its proper divisors (36059589168).

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

21231422544 is a wasteful number, since it uses less digits than its factorization.

21231422544 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19684 (or 19678 counting only the distinct ones).

The product of its digits is 15360, while the sum is 30.

Adding to 21231422544 its reverse (44522413212), we get a palindrome (65753835756).

The spelling of 21231422544 in words is "twenty-one billion, two hundred thirty-one million, four hundred twenty-two thousand, five hundred forty-four".