21517702661353 has 4 divisors (see below), whose sum is σ = 22650213327760. Its totient is φ = 20385191994948.

The previous prime is 21517702661309. The next prime is 21517702661383. The reversal of 21517702661353 is 35316620771512.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21517702661353 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21517702661297 and 21517702661306.

It is not an unprimeable number, because it can be changed into a prime (21517702661383) 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, 566255333175 + ... + 566255333212.

It is an arithmetic number, because the mean of its divisors is an integer number (5662553331940).

Almost surely, 2^{21517702661353} is an apocalyptic number.

It is an amenable number.

21517702661353 is a deficient number, since it is larger than the sum of its proper divisors (1132510666407).

21517702661353 is a wasteful number, since it uses less digits than its factorization.

21517702661353 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1132510666406.

The product of its (nonzero) digits is 1587600, while the sum is 49.

The spelling of 21517702661353 in words is "twenty-one trillion, five hundred seventeen billion, seven hundred two million, six hundred sixty-one thousand, three hundred fifty-three".