1240547257 has 2 divisors, whose sum is σ = 1240547258. Its totient is φ = 1240547256.

The previous prime is 1240547233. The next prime is 1240547293. The reversal of 1240547257 is 7527450421.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1239814521 + 732736 = 35211^2 + 856^2 .

It is an emirp because it is prime and its reverse (7527450421) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1240547257 - 2⁷ = 1240547129 is a prime.

It is not a weakly prime, because it can be changed into another prime (1240547207) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 620273628 + 620273629.

It is an arithmetic number, because the mean of its divisors is an integer number (620273629).

Almost surely, 2^1240547257 is an apocalyptic number.

It is an amenable number.

1240547257 is a deficient number, since it is larger than the sum of its proper divisors (1).

1240547257 is an equidigital number, since it uses as much as digits as its factorization.

1240547257 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 78400, while the sum is 37.

The square root of 1240547257 is about 35221.4033933914. The cubic root of 1240547257 is about 1074.4950957231.

Adding to 1240547257 its reverse (7527450421), we get a palindrome (8767997678).

The spelling of 1240547257 in words is "one billion, two hundred forty million, five hundred forty-seven thousand, two hundred fifty-seven".