20197757 has 2 divisors, whose sum is σ = 20197758. Its totient is φ = 20197756.

The previous prime is 20197747. The next prime is 20197759. The reversal of 20197757 is 75779102.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13942756 + 6255001 = 3734^2 + 2501^2 .

It is a cyclic number.

It is not a de Polignac number, because 20197757 - 2⁸ = 20197501 is a prime.

Together with 20197759, it forms a pair of twin primes.

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 20197757.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20197759) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10098878 + 10098879.

It is an arithmetic number, because the mean of its divisors is an integer number (10098879).

Almost surely, 2^20197757 is an apocalyptic number.

It is an amenable number.

20197757 is a deficient number, since it is larger than the sum of its proper divisors (1).

20197757 is an equidigital number, since it uses as much as digits as its factorization.

20197757 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 30870, while the sum is 38.

The square root of 20197757 is about 4494.1914734466. The cubic root of 20197757 is about 272.3334874764. Note that the first 3 decimals are identical.

The spelling of 20197757 in words is "twenty million, one hundred ninety-seven thousand, seven hundred fifty-seven".