21317459 has 4 divisors (see below), whose sum is σ = 21339360. Its totient is φ = 21295560.

The previous prime is 21317447. The next prime is 21317479. The reversal of 21317459 is 95471312.

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 21317459 - 2¹² = 21313363 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21317419) 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, 9419 + ... + 11460.

It is an arithmetic number, because the mean of its divisors is an integer number (5334840).

Almost surely, 2^21317459 is an apocalyptic number.

21317459 is a deficient number, since it is larger than the sum of its proper divisors (21901).

21317459 is a wasteful number, since it uses less digits than its factorization.

21317459 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21900.

The product of its digits is 7560, while the sum is 32.

The square root of 21317459 is about 4617.0833867280. The cubic root of 21317459 is about 277.2757011205.

The spelling of 21317459 in words is "twenty-one million, three hundred seventeen thousand, four hundred fifty-nine".