21745515346321 has 8 divisors (see below), whose sum is σ = 23989424059944. Its totient is φ = 19583203313280.

The previous prime is 21745515346279. The next prime is 21745515346337. The reversal of 21745515346321 is 12364351554712.

It can be written as a sum of positive squares in 4 ways, for example, as 273412906321 + 21472102440000 = 522889^2 + 4633800^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21745515346321 - 2²¹ = 21745513249169 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21745515340321) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 20399169586 + ... + 20399170651.

It is an arithmetic number, because the mean of its divisors is an integer number (2998678007493).

Almost surely, 2^{21745515346321} is an apocalyptic number.

It is an amenable number.

21745515346321 is a deficient number, since it is larger than the sum of its proper divisors (2243908713623).

21745515346321 is a wasteful number, since it uses less digits than its factorization.

21745515346321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40798340291.

The product of its digits is 3024000, while the sum is 49.

The spelling of 21745515346321 in words is "twenty-one trillion, seven hundred forty-five billion, five hundred fifteen million, three hundred forty-six thousand, three hundred twenty-one".