1231557893 has 2 divisors, whose sum is σ = 1231557894. Its totient is φ = 1231557892.

The previous prime is 1231557851. The next prime is 1231557907. The reversal of 1231557893 is 3987551321.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 878944609 + 352613284 = 29647^2 + 18778^2 .

It is a cyclic number.

It is not a de Polignac number, because 1231557893 - 2¹⁶ = 1231492357 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1231557293) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 615778946 + 615778947.

It is an arithmetic number, because the mean of its divisors is an integer number (615778947).

Almost surely, 2^1231557893 is an apocalyptic number.

It is an amenable number.

1231557893 is a deficient number, since it is larger than the sum of its proper divisors (1).

1231557893 is an equidigital number, since it uses as much as digits as its factorization.

1231557893 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 226800, while the sum is 44.

The square root of 1231557893 is about 35093.5591383946. The cubic root of 1231557893 is about 1071.8934340887.

The spelling of 1231557893 in words is "one billion, two hundred thirty-one million, five hundred fifty-seven thousand, eight hundred ninety-three".