21922517 has 2 divisors, whose sum is σ = 21922518. Its totient is φ = 21922516.

The previous prime is 21922513. The next prime is 21922529. The reversal of 21922517 is 71522912.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21215236 + 707281 = 4606^2 + 841^2 .

It is a cyclic number.

It is not a de Polignac number, because 21922517 - 2² = 21922513 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21922517.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21922513) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10961258 + 10961259.

It is an arithmetic number, because the mean of its divisors is an integer number (10961259).

Almost surely, 2^21922517 is an apocalyptic number.

It is an amenable number.

21922517 is a deficient number, since it is larger than the sum of its proper divisors (1).

21922517 is an equidigital number, since it uses as much as digits as its factorization.

21922517 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2520, while the sum is 29.

The square root of 21922517 is about 4682.1487588499. The cubic root of 21922517 is about 279.8745909478.

The spelling of 21922517 in words is "twenty-one million, nine hundred twenty-two thousand, five hundred seventeen".