21874717 has 4 divisors (see below), whose sum is σ = 21885916. Its totient is φ = 21863520.

The previous prime is 21874711. The next prime is 21874751. The reversal of 21874717 is 71747812.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 1705636 + 20169081 = 1306^2 + 4491^2 .

It is a cyclic number.

It is not a de Polignac number, because 21874717 - 2³ = 21874709 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21874711) 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, 1818 + ... + 6859.

It is an arithmetic number, because the mean of its divisors is an integer number (5471479).

Almost surely, 2^21874717 is an apocalyptic number.

It is an amenable number.

21874717 is a deficient number, since it is larger than the sum of its proper divisors (11199).

21874717 is an equidigital number, since it uses as much as digits as its factorization.

21874717 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11198.

The product of its digits is 21952, while the sum is 37.

The square root of 21874717 is about 4677.0414793970. The cubic root of 21874717 is about 279.6710294619.

The spelling of 21874717 in words is "twenty-one million, eight hundred seventy-four thousand, seven hundred seventeen".