21794917 has 4 divisors (see below), whose sum is σ = 21814380. Its totient is φ = 21775456.

The previous prime is 21794879. The next prime is 21794933. The reversal of 21794917 is 71949712.

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 13535041 + 8259876 = 3679^2 + 2874^2 .

It is a cyclic number.

It is not a de Polignac number, because 21794917 - 2⁷ = 21794789 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21794917.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21794947) 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, 7942 + ... + 10327.

It is an arithmetic number, because the mean of its divisors is an integer number (5453595).

Almost surely, 2^21794917 is an apocalyptic number.

It is an amenable number.

21794917 is a deficient number, since it is larger than the sum of its proper divisors (19463).

21794917 is a wasteful number, since it uses less digits than its factorization.

21794917 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19462.

The product of its digits is 31752, while the sum is 40.

The square root of 21794917 is about 4668.5026507436. The cubic root of 21794917 is about 279.3305307023.

The spelling of 21794917 in words is "twenty-one million, seven hundred ninety-four thousand, nine hundred seventeen".