1257491849 has 2 divisors, whose sum is σ = 1257491850. Its totient is φ = 1257491848.

The previous prime is 1257491831. The next prime is 1257491861. The reversal of 1257491849 is 9481947521.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1180403449 + 77088400 = 34357^2 + 8780^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1257491849 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1257491797 and 1257491806.

It is not a weakly prime, because it can be changed into another prime (1257491869) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 628745924 + 628745925.

It is an arithmetic number, because the mean of its divisors is an integer number (628745925).

Almost surely, 2^1257491849 is an apocalyptic number.

It is an amenable number.

1257491849 is a deficient number, since it is larger than the sum of its proper divisors (1).

1257491849 is an equidigital number, since it uses as much as digits as its factorization.

1257491849 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 725760, while the sum is 50.

The square root of 1257491849 is about 35461.1315245298. The cubic root of 1257491849 is about 1079.3651530168.

The spelling of 1257491849 in words is "one billion, two hundred fifty-seven million, four hundred ninety-one thousand, eight hundred forty-nine".