21692569 has 2 divisors, whose sum is σ = 21692570. Its totient is φ = 21692568.

The previous prime is 21692557. The next prime is 21692579. The reversal of 21692569 is 96529612.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17530969 + 4161600 = 4187^2 + 2040^2 .

It is a cyclic number.

It is not a de Polignac number, because 21692569 - 2¹⁵ = 21659801 is a prime.

It is a super-2 number, since 2×21692569² = 941135099639522, which contains 22 as substring.

It is a Chen prime.

It is an alternating number because its digits alternate between even and odd.

It is not a weakly prime, because it can be changed into another prime (21692549) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10846284 + 10846285.

It is an arithmetic number, because the mean of its divisors is an integer number (10846285).

Almost surely, 2^21692569 is an apocalyptic number.

It is an amenable number.

21692569 is a deficient number, since it is larger than the sum of its proper divisors (1).

21692569 is an equidigital number, since it uses as much as digits as its factorization.

21692569 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 58320, while the sum is 40.

The square root of 21692569 is about 4657.5282071073. The cubic root of 21692569 is about 278.8926030721.

The spelling of 21692569 in words is "twenty-one million, six hundred ninety-two thousand, five hundred sixty-nine".