21717151662617 has 4 divisors (see below), whose sum is σ = 22860159644880. Its totient is φ = 20574143680356.

The previous prime is 21717151662589. The next prime is 21717151662637. The reversal of 21717151662617 is 71626615171712.

It is a happy number.

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 not a de Polignac number, because 21717151662617 - 2⁶ = 21717151662553 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21717151662637) 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, 571503991103 + ... + 571503991140.

It is an arithmetic number, because the mean of its divisors is an integer number (5715039911220).

Almost surely, 2^{21717151662617} is an apocalyptic number.

It is an amenable number.

21717151662617 is a deficient number, since it is larger than the sum of its proper divisors (1143007982263).

21717151662617 is a wasteful number, since it uses less digits than its factorization.

21717151662617 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1143007982262.

The product of its digits is 1481760, while the sum is 53.

The spelling of 21717151662617 in words is "twenty-one trillion, seven hundred seventeen billion, one hundred fifty-one million, six hundred sixty-two thousand, six hundred seventeen".