249991057 has 2 divisors, whose sum is σ = 249991058. Its totient is φ = 249991056.

The previous prime is 249991043. The next prime is 249991081. The reversal of 249991057 is 750199942.

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., 182898576 + 67092481 = 13524^2 + 8191^2 .

It is a cyclic number.

It is not a de Polignac number, because 249991057 - 2¹¹ = 249989009 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 249990998 and 249991016.

It is not a weakly prime, because it can be changed into another prime (249991087) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 124995528 + 124995529.

It is an arithmetic number, because the mean of its divisors is an integer number (124995529).

Almost surely, 2^249991057 is an apocalyptic number.

It is an amenable number.

249991057 is a deficient number, since it is larger than the sum of its proper divisors (1).

249991057 is an equidigital number, since it uses as much as digits as its factorization.

249991057 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 204120, while the sum is 46.

The square root of 249991057 is about 15811.1054958216. The cubic root of 249991057 is about 629.9530132086.

The spelling of 249991057 in words is "two hundred forty-nine million, nine hundred ninety-one thousand, fifty-seven".