21617653171 has 4 divisors (see below), whose sum is σ = 21618664344. Its totient is φ = 21616642000.

The previous prime is 21617653139. The next prime is 21617653217. The reversal of 21617653171 is 17135671612.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21617653171 - 2⁵ = 21617653139 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21617654171) 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, 472810 + ... + 516511.

It is an arithmetic number, because the mean of its divisors is an integer number (5404666086).

Almost surely, 2^21617653171 is an apocalyptic number.

21617653171 is a deficient number, since it is larger than the sum of its proper divisors (1011173).

21617653171 is an equidigital number, since it uses as much as digits as its factorization.

21617653171 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1011172.

The product of its digits is 52920, while the sum is 40.

The spelling of 21617653171 in words is "twenty-one billion, six hundred seventeen million, six hundred fifty-three thousand, one hundred seventy-one".