21994307 has 4 divisors (see below), whose sum is σ = 22007256. Its totient is φ = 21981360.

The previous prime is 21994237. The next prime is 21994319. The reversal of 21994307 is 70349912.

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 21994307 - 2²⁰ = 20945731 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21994367) 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, 3458 + ... + 7479.

It is an arithmetic number, because the mean of its divisors is an integer number (5501814).

Almost surely, 2^21994307 is an apocalyptic number.

21994307 is a deficient number, since it is larger than the sum of its proper divisors (12949).

21994307 is a wasteful number, since it uses less digits than its factorization.

21994307 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12948.

The product of its (nonzero) digits is 13608, while the sum is 35.

The square root of 21994307 is about 4689.8088447185. The cubic root of 21994307 is about 280.1797612684.

The spelling of 21994307 in words is "twenty-one million, nine hundred ninety-four thousand, three hundred seven".