1261259551 has 2 divisors, whose sum is σ = 1261259552. Its totient is φ = 1261259550.

The previous prime is 1261259477. The next prime is 1261259591. The reversal of 1261259551 is 1559521621.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1261259551 - 2²³ = 1252870943 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1261259551.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1261259591) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 630629775 + 630629776.

It is an arithmetic number, because the mean of its divisors is an integer number (630629776).

Almost surely, 2^1261259551 is an apocalyptic number.

1261259551 is a deficient number, since it is larger than the sum of its proper divisors (1).

1261259551 is an equidigital number, since it uses as much as digits as its factorization.

1261259551 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 27000, while the sum is 37.

The square root of 1261259551 is about 35514.2161816926. The cubic root of 1261259551 is about 1080.4420775355.

The spelling of 1261259551 in words is "one billion, two hundred sixty-one million, two hundred fifty-nine thousand, five hundred fifty-one".