1231242757 has 2 divisors, whose sum is σ = 1231242758. Its totient is φ = 1231242756.

The previous prime is 1231242659. The next prime is 1231242767. The reversal of 1231242757 is 7572421321.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 981318276 + 249924481 = 31326^2 + 15809^2 .

It is an emirp because it is prime and its reverse (7572421321) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1231242757 - 2²⁷ = 1097025029 is a prime.

It is a super-2 number, since 2×1231242757² = 3031917453329922098, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1231242767) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 615621378 + 615621379.

It is an arithmetic number, because the mean of its divisors is an integer number (615621379).

Almost surely, 2^1231242757 is an apocalyptic number.

It is an amenable number.

1231242757 is a deficient number, since it is larger than the sum of its proper divisors (1).

1231242757 is an equidigital number, since it uses as much as digits as its factorization.

1231242757 is an evil number, because the sum of its binary digits is even.

The product of its digits is 23520, while the sum is 34.

The square root of 1231242757 is about 35089.0689104171. The cubic root of 1231242757 is about 1071.8019994846.

The spelling of 1231242757 in words is "one billion, two hundred thirty-one million, two hundred forty-two thousand, seven hundred fifty-seven".