21540344433472 has 28 divisors (see below), whose sum is σ = 42837653036740. Its totient is φ = 10746605085696.

The previous prime is 21540344433469. The next prime is 21540344433479. The reversal of 21540344433472 is 27433444304512.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 20385441720576 + 1154902712896 = 4515024^2 + 1074664^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21540344433479) 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, 368206947 + ... + 368265442.

Almost surely, 2^{21540344433472} is an apocalyptic number.

It is an amenable number.

21540344433472 is a deficient number, since it is larger than the sum of its proper divisors (21297308603268).

21540344433472 is an equidigital number, since it uses as much as digits as its factorization.

21540344433472 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 736472858 (or 736472848 counting only the distinct ones).

The product of its (nonzero) digits is 3870720, while the sum is 46.

Adding to 21540344433472 its reverse (27433444304512), we get a palindrome (48973788737984).

The spelling of 21540344433472 in words is "twenty-one trillion, five hundred forty billion, three hundred forty-four million, four hundred thirty-three thousand, four hundred seventy-two".