20557907 has 2 divisors, whose sum is σ = 20557908. Its totient is φ = 20557906.

The previous prime is 20557891. The next prime is 20557909. The reversal of 20557907 is 70975502.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20557907 - 2⁴ = 20557891 is a prime.

Together with 20557909, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (20557909) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10278953 + 10278954.

It is an arithmetic number, because the mean of its divisors is an integer number (10278954).

Almost surely, 2^20557907 is an apocalyptic number.

20557907 is a deficient number, since it is larger than the sum of its proper divisors (1).

20557907 is an equidigital number, since it uses as much as digits as its factorization.

20557907 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 22050, while the sum is 35.

The square root of 20557907 is about 4534.0828179468. The cubic root of 20557907 is about 273.9426372183.

The spelling of 20557907 in words is "twenty million, five hundred fifty-seven thousand, nine hundred seven".