21174247 has 4 divisors (see below), whose sum is σ = 21220056. Its totient is φ = 21128440.

The previous prime is 21174239. The next prime is 21174253. The reversal of 21174247 is 74247112.

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 21174247 - 2³ = 21174239 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 (21174217) 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, 22204 + ... + 23137.

It is an arithmetic number, because the mean of its divisors is an integer number (5305014).

Almost surely, 2^21174247 is an apocalyptic number.

21174247 is a deficient number, since it is larger than the sum of its proper divisors (45809).

21174247 is an equidigital number, since it uses as much as digits as its factorization.

21174247 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45808.

The product of its digits is 3136, while the sum is 28.

The square root of 21174247 is about 4601.5483263789. The cubic root of 21174247 is about 276.6533870499.

The spelling of 21174247 in words is "twenty-one million, one hundred seventy-four thousand, two hundred forty-seven".