1261332551 has 2 divisors, whose sum is σ = 1261332552. Its totient is φ = 1261332550.

The previous prime is 1261332533. The next prime is 1261332571. The reversal of 1261332551 is 1552331621.

It is a weak prime.

It is an emirp because it is prime and its reverse (1552331621) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1261332551 - 2³⁰ = 187590727 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1261332511) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 630666275 + 630666276.

It is an arithmetic number, because the mean of its divisors is an integer number (630666276).

Almost surely, 2^1261332551 is an apocalyptic number.

1261332551 is a deficient number, since it is larger than the sum of its proper divisors (1).

1261332551 is an equidigital number, since it uses as much as digits as its factorization.

1261332551 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5400, while the sum is 29.

The square root of 1261332551 is about 35515.2439242644. The cubic root of 1261332551 is about 1080.4629219763.

The spelling of 1261332551 in words is "one billion, two hundred sixty-one million, three hundred thirty-two thousand, five hundred fifty-one".