209400857 has 2 divisors, whose sum is σ = 209400858. Its totient is φ = 209400856.

The previous prime is 209400847. The next prime is 209400889. The reversal of 209400857 is 758004902.

It is a happy number.

209400857 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 182142016 + 27258841 = 13496^2 + 5221^2 .

It is a cyclic number.

It is not a de Polignac number, because 209400857 - 2²² = 205206553 is a prime.

It is not a weakly prime, because it can be changed into another prime (209400847) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 104700428 + 104700429.

It is an arithmetic number, because the mean of its divisors is an integer number (104700429).

Almost surely, 2^209400857 is an apocalyptic number.

It is an amenable number.

209400857 is a deficient number, since it is larger than the sum of its proper divisors (1).

209400857 is an equidigital number, since it uses as much as digits as its factorization.

209400857 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 20160, while the sum is 35.

The square root of 209400857 is about 14470.6895827393. The cubic root of 209400857 is about 593.8263775874.

The spelling of 209400857 in words is "two hundred nine million, four hundred thousand, eight hundred fifty-seven".