21353717 has 24 divisors (see below), whose sum is σ = 28421568. Its totient is φ = 15649920.

The previous prime is 21353711. The next prime is 21353737. The reversal of 21353717 is 71735312.

It is not a de Polignac number, because 21353717 - 2⁸ = 21353461 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21353717.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21353711) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 13658 + ... + 15140.

It is an arithmetic number, because the mean of its divisors is an integer number (1184232).

Almost surely, 2^21353717 is an apocalyptic number.

It is an amenable number.

21353717 is a deficient number, since it is larger than the sum of its proper divisors (7067851).

21353717 is a wasteful number, since it uses less digits than its factorization.

21353717 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1529 (or 1518 counting only the distinct ones).

The product of its digits is 4410, while the sum is 29.

The square root of 21353717 is about 4621.0082233210. The cubic root of 21353717 is about 277.4328144035.

The spelling of 21353717 in words is "twenty-one million, three hundred fifty-three thousand, seven hundred seventeen".