21715051171 has 16 divisors (see below), whose sum is σ = 24093974880. Its totient is φ = 19406168320.

The previous prime is 21715051129. The next prime is 21715051217. The reversal of 21715051171 is 17115051712.

It is a de Polignac number, because none of the positive numbers 2^k-21715051171 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21715052171) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 105261 + ... + 233473.

It is an arithmetic number, because the mean of its divisors is an integer number (1505873430).

Almost surely, 2^21715051171 is an apocalyptic number.

21715051171 is a deficient number, since it is larger than the sum of its proper divisors (2378923709).

21715051171 is a wasteful number, since it uses less digits than its factorization.

21715051171 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 128486.

The product of its (nonzero) digits is 2450, while the sum is 31.

It can be divided in two parts, 2171505 and 1171, that added together give a square (2172676 = 1474²).

The spelling of 21715051171 in words is "twenty-one billion, seven hundred fifteen million, fifty-one thousand, one hundred seventy-one".