1231262521 has 2 divisors, whose sum is σ = 1231262522. Its totient is φ = 1231262520.

The previous prime is 1231262449. The next prime is 1231262531. The reversal of 1231262521 is 1252621321.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 753228025 + 478034496 = 27445^2 + 21864^2 .

It is a cyclic number.

It is not a de Polignac number, because 1231262521 - 2¹¹ = 1231260473 is a prime.

It is not a weakly prime, because it can be changed into another prime (1231262531) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 615631260 + 615631261.

It is an arithmetic number, because the mean of its divisors is an integer number (615631261).

Almost surely, 2^1231262521 is an apocalyptic number.

It is an amenable number.

1231262521 is a deficient number, since it is larger than the sum of its proper divisors (1).

1231262521 is an equidigital number, since it uses as much as digits as its factorization.

1231262521 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1440, while the sum is 25.

The square root of 1231262521 is about 35089.3505354545. The cubic root of 1231262521 is about 1071.8077343356.

Adding to 1231262521 its reverse (1252621321), we get a palindrome (2483883842).

The spelling of 1231262521 in words is "one billion, two hundred thirty-one million, two hundred sixty-two thousand, five hundred twenty-one".