1261561 has 8 divisors (see below), whose sum is σ = 1449920. Its totient is φ = 1075248.

The previous prime is 1261549. The next prime is 1261567. The reversal of 1261561 is 1651621.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1261561 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1261567) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1210 + ... + 1996.

It is an arithmetic number, because the mean of its divisors is an integer number (181240).

2^1261561 is an apocalyptic number.

It is an amenable number.

1261561 is a deficient number, since it is larger than the sum of its proper divisors (188359).

1261561 is an equidigital number, since it uses as much as digits as its factorization.

1261561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1023.

The product of its digits is 360, while the sum is 22.

The square root of 1261561 is about 1123.1923254724. The cubic root of 1261561 is about 108.0528148173.

The spelling of 1261561 in words is "one million, two hundred sixty-one thousand, five hundred sixty-one".