1266761261 has 4 divisors (see below), whose sum is σ = 1273760124. Its totient is φ = 1259762400.

The previous prime is 1266761219. The next prime is 1266761333. The reversal of 1266761261 is 1621676621.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 83814025 + 1182947236 = 9155^2 + 34394^2 .

It is a cyclic number.

It is not a de Polignac number, because 1266761261 - 2²² = 1262566957 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1266761201) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3499160 + ... + 3499521.

It is an arithmetic number, because the mean of its divisors is an integer number (318440031).

Almost surely, 2^1266761261 is an apocalyptic number.

It is an amenable number.

1266761261 is a deficient number, since it is larger than the sum of its proper divisors (6998863).

1266761261 is an equidigital number, since it uses as much as digits as its factorization.

1266761261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6998862.

The product of its digits is 36288, while the sum is 38.

The square root of 1266761261 is about 35591.5897509510. The cubic root of 1266761261 is about 1082.0107889426.

The spelling of 1266761261 in words is "one billion, two hundred sixty-six million, seven hundred sixty-one thousand, two hundred sixty-one".