1261251745 has 16 divisors (see below), whose sum is σ = 1673980560. Its totient is φ = 906211584.

The previous prime is 1261251737. The next prime is 1261251757. The reversal of 1261251745 is 5471521621.

It can be written as a sum of positive squares in 8 ways, for example, as 64368529 + 1196883216 = 8023^2 + 34596^2 .

It is a cyclic number.

It is not a de Polignac number, because 1261251745 - 2³ = 1261251737 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1261251745.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 259810 + ... + 264619.

It is an arithmetic number, because the mean of its divisors is an integer number (104623785).

Almost surely, 2^1261251745 is an apocalyptic number.

It is an amenable number.

1261251745 is a deficient number, since it is larger than the sum of its proper divisors (412728815).

1261251745 is a wasteful number, since it uses less digits than its factorization.

1261251745 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 524484.

The product of its digits is 16800, while the sum is 34.

The square root of 1261251745 is about 35514.1062818706. The cubic root of 1261251745 is about 1080.4398485604.

The spelling of 1261251745 in words is "one billion, two hundred sixty-one million, two hundred fifty-one thousand, seven hundred forty-five".