20909297 has 2 divisors, whose sum is σ = 20909298. Its totient is φ = 20909296.

The previous prime is 20909281. The next prime is 20909311. The reversal of 20909297 is 79290902.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15358561 + 5550736 = 3919^2 + 2356^2 .

It is a cyclic number.

It is not a de Polignac number, because 20909297 - 2⁴ = 20909281 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20909297.

It is not a weakly prime, because it can be changed into another prime (20909897) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10454648 + 10454649.

It is an arithmetic number, because the mean of its divisors is an integer number (10454649).

Almost surely, 2^20909297 is an apocalyptic number.

It is an amenable number.

20909297 is a deficient number, since it is larger than the sum of its proper divisors (1).

20909297 is an equidigital number, since it uses as much as digits as its factorization.

20909297 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 20412, while the sum is 38.

The square root of 20909297 is about 4572.6684769399. The cubic root of 20909297 is about 275.4946337515.

The spelling of 20909297 in words is "twenty million, nine hundred nine thousand, two hundred ninety-seven".