21712317 has 16 divisors (see below), whose sum is σ = 32017728. Its totient is φ = 12977280.

The previous prime is 21712309. The next prime is 21712319. The reversal of 21712317 is 71321712.

It is not a de Polignac number, because 21712317 - 2³ = 21712309 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21712319) 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, 2098 + ... + 6915.

It is an arithmetic number, because the mean of its divisors is an integer number (2001108).

Almost surely, 2^21712317 is an apocalyptic number.

It is an amenable number.

21712317 is a deficient number, since it is larger than the sum of its proper divisors (10305411).

21712317 is a wasteful number, since it uses less digits than its factorization.

21712317 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9100.

The product of its digits is 588, while the sum is 24.

The square root of 21712317 is about 4659.6477334666. The cubic root of 21712317 is about 278.9772080918.

The spelling of 21712317 in words is "twenty-one million, seven hundred twelve thousand, three hundred seventeen".