21722297 has 2 divisors, whose sum is σ = 21722298. Its totient is φ = 21722296.

The previous prime is 21722291. The next prime is 21722317. The reversal of 21722297 is 79222712.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11806096 + 9916201 = 3436^2 + 3149^2 .

It is a cyclic number.

It is not a de Polignac number, because 21722297 - 2¹² = 21718201 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21722291) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10861148 + 10861149.

It is an arithmetic number, because the mean of its divisors is an integer number (10861149).

Almost surely, 2^21722297 is an apocalyptic number.

It is an amenable number.

21722297 is a deficient number, since it is larger than the sum of its proper divisors (1).

21722297 is an equidigital number, since it uses as much as digits as its factorization.

21722297 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7056, while the sum is 32.

The square root of 21722297 is about 4660.7185068399. The cubic root of 21722297 is about 279.0199452175.

The spelling of 21722297 in words is "twenty-one million, seven hundred twenty-two thousand, two hundred ninety-seven".