21312432225440 has 24 divisors (see below), whose sum is σ = 50350621132980. Its totient is φ = 8524972890112.

The previous prime is 21312432225397. The next prime is 21312432225443. The reversal of 21312432225440 is 4452223421312.

It can be written as a sum of positive squares in 2 ways, for example, as 18994011836944 + 2318420388496 = 4358212^2 + 1522636^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21312432225440.

It is not an unprimeable number, because it can be changed into a prime (21312432225443) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 66601350545 + ... + 66601350864.

Almost surely, 2^{21312432225440} is an apocalyptic number.

21312432225440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21312432225440 is an abundant number, since it is smaller than the sum of its proper divisors (29038188907540).

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

21312432225440 is a wasteful number, since it uses less digits than its factorization.

21312432225440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 133202701424 (or 133202701416 counting only the distinct ones).

The product of its (nonzero) digits is 92160, while the sum is 35.

Adding to 21312432225440 its reverse (4452223421312), we get a palindrome (25764655646752).

The spelling of 21312432225440 in words is "twenty-one trillion, three hundred twelve billion, four hundred thirty-two million, two hundred twenty-five thousand, four hundred forty".