21274717 has 4 divisors (see below), whose sum is σ = 21357756. Its totient is φ = 21191680.

The previous prime is 21274709. The next prime is 21274727. The reversal of 21274717 is 71747212.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 12916836 + 8357881 = 3594^2 + 2891^2 .

It is a cyclic number.

It is not a de Polignac number, because 21274717 - 2³ = 21274709 is a prime.

It is a super-2 number, since 2×21274717² = 905227166860178, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21274727) 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, 41134 + ... + 41647.

It is an arithmetic number, because the mean of its divisors is an integer number (5339439).

Almost surely, 2^21274717 is an apocalyptic number.

It is an amenable number.

21274717 is a deficient number, since it is larger than the sum of its proper divisors (83039).

21274717 is an equidigital number, since it uses as much as digits as its factorization.

21274717 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 83038.

The product of its digits is 5488, while the sum is 31.

The square root of 21274717 is about 4612.4523845781. The cubic root of 21274717 is about 277.0902623904.

The spelling of 21274717 in words is "twenty-one million, two hundred seventy-four thousand, seven hundred seventeen".