21317853 has 8 divisors (see below), whose sum is σ = 28890016. Its totient is φ = 13978800.

The previous prime is 21317851. The next prime is 21317861. The reversal of 21317853 is 35871312.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21317853 - 2¹ = 21317851 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21317853.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21317851) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 58063 + ... + 58428.

It is an arithmetic number, because the mean of its divisors is an integer number (3611252).

Almost surely, 2^21317853 is an apocalyptic number.

It is an amenable number.

21317853 is a deficient number, since it is larger than the sum of its proper divisors (7572163).

21317853 is a wasteful number, since it uses less digits than its factorization.

21317853 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 116555.

The product of its digits is 5040, while the sum is 30.

The square root of 21317853 is about 4617.1260541597. The cubic root of 21317853 is about 277.2774093596.

The spelling of 21317853 in words is "twenty-one million, three hundred seventeen thousand, eight hundred fifty-three".