1260331561 has 4 divisors (see below), whose sum is σ = 1303791300. Its totient is φ = 1216871824.

The previous prime is 1260331559. The next prime is 1260331577. The reversal of 1260331561 is 1651330621.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1651330621 = 15737 ⋅104933.

It can be written as a sum of positive squares in 2 ways, for example, as 198810000 + 1061521561 = 14100^2 + 32581^2 .

It is a cyclic number.

It is not a de Polignac number, because 1260331561 - 2¹ = 1260331559 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1260331531) 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, 21729826 + ... + 21729883.

It is an arithmetic number, because the mean of its divisors is an integer number (325947825).

Almost surely, 2^1260331561 is an apocalyptic number.

It is an amenable number.

1260331561 is a deficient number, since it is larger than the sum of its proper divisors (43459739).

1260331561 is an equidigital number, since it uses as much as digits as its factorization.

1260331561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43459738.

The product of its (nonzero) digits is 3240, while the sum is 28.

The square root of 1260331561 is about 35501.1487278933. The cubic root of 1260331561 is about 1080.1770288796.

The spelling of 1260331561 in words is "one billion, two hundred sixty million, three hundred thirty-one thousand, five hundred sixty-one".