20897759 has 2 divisors, whose sum is σ = 20897760. Its totient is φ = 20897758.

The previous prime is 20897753. The next prime is 20897761. The reversal of 20897759 is 95779802.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20897759 is a prime.

Together with 20897761, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20897753) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10448879 + 10448880.

It is an arithmetic number, because the mean of its divisors is an integer number (10448880).

Almost surely, 2^20897759 is an apocalyptic number.

20897759 is a deficient number, since it is larger than the sum of its proper divisors (1).

20897759 is an equidigital number, since it uses as much as digits as its factorization.

20897759 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 317520, while the sum is 47.

The square root of 20897759 is about 4571.4066762869. The cubic root of 20897759 is about 275.4439506840.

The spelling of 20897759 in words is "twenty million, eight hundred ninety-seven thousand, seven hundred fifty-nine".