21722207 has 16 divisors (see below), whose sum is σ = 24084480. Its totient is φ = 19468512.

The previous prime is 21722203. The next prime is 21722213. The reversal of 21722207 is 70222712.

It is a cyclic number.

It is not a de Polignac number, because 21722207 - 2² = 21722203 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 (21722201) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 97298 + ... + 97520.

It is an arithmetic number, because the mean of its divisors is an integer number (1505280).

Almost surely, 2^21722207 is an apocalyptic number.

21722207 is a deficient number, since it is larger than the sum of its proper divisors (2362273).

21722207 is a wasteful number, since it uses less digits than its factorization.

21722207 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 422.

The product of its (nonzero) digits is 784, while the sum is 23.

The square root of 21722207 is about 4660.7088516662. The cubic root of 21722207 is about 279.0195598710.

Adding to 21722207 its reverse (70222712), we get a palindrome (91944919).

The spelling of 21722207 in words is "twenty-one million, seven hundred twenty-two thousand, two hundred seven".