1261555360 has 96 divisors (see below), whose sum is σ = 3217938192. Its totient is φ = 464609280.

The previous prime is 1261555349. The next prime is 1261555387. The reversal of 1261555360 is 635551621.

It can be written as a sum of positive squares in 8 ways, for example, as 26173456 + 1235381904 = 5116^2 + 35148^2 .

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, 1582482 + ... + 1583278.

Almost surely, 2^1261555360 is an apocalyptic number.

1261555360 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1261555360, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1608969096).

1261555360 is an abundant number, since it is smaller than the sum of its proper divisors (1956382832).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1261555360 is a wasteful number, since it uses less digits than its factorization.

1261555360 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1586 (or 1578 counting only the distinct ones).

The product of its (nonzero) digits is 27000, while the sum is 34.

The square root of 1261555360 is about 35518.3805937151. The cubic root of 1261555360 is about 1080.5265379485.

The spelling of 1261555360 in words is "one billion, two hundred sixty-one million, five hundred fifty-five thousand, three hundred sixty".