20489257 has 2 divisors, whose sum is σ = 20489258. Its totient is φ = 20489256.

The previous prime is 20489237. The next prime is 20489269. The reversal of 20489257 is 75298402.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16818201 + 3671056 = 4101^2 + 1916^2 .

It is a cyclic number.

It is not a de Polignac number, because 20489257 - 2¹⁹ = 19964969 is a prime.

It is not a weakly prime, because it can be changed into another prime (20489237) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10244628 + 10244629.

It is an arithmetic number, because the mean of its divisors is an integer number (10244629).

Almost surely, 2^20489257 is an apocalyptic number.

It is an amenable number.

20489257 is a deficient number, since it is larger than the sum of its proper divisors (1).

20489257 is an equidigital number, since it uses as much as digits as its factorization.

20489257 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 40320, while the sum is 37.

The square root of 20489257 is about 4526.5060477149. The cubic root of 20489257 is about 273.6373672573.

The spelling of 20489257 in words is "twenty million, four hundred eighty-nine thousand, two hundred fifty-seven".