20430857 has 2 divisors, whose sum is σ = 20430858. Its totient is φ = 20430856.

The previous prime is 20430841. The next prime is 20430899. The reversal of 20430857 is 75803402.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11316496 + 9114361 = 3364^2 + 3019^2 .

It is a cyclic number.

It is not a de Polignac number, because 20430857 - 2⁴ = 20430841 is a prime.

It is a Chen prime.

It is equal to p_1296164 and since 20430857 and 1296164 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (20430827) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10215428 + 10215429.

It is an arithmetic number, because the mean of its divisors is an integer number (10215429).

Almost surely, 2^20430857 is an apocalyptic number.

It is an amenable number.

20430857 is a deficient number, since it is larger than the sum of its proper divisors (1).

20430857 is an equidigital number, since it uses as much as digits as its factorization.

20430857 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6720, while the sum is 29.

The square root of 20430857 is about 4520.0505528146. The cubic root of 20430857 is about 273.3771393535.

The spelling of 20430857 in words is "twenty million, four hundred thirty thousand, eight hundred fifty-seven".