1309561 has 16 divisors (see below), whose sum is σ = 1555200. Its totient is φ = 1089280.

The previous prime is 1309559. The next prime is 1309571. The reversal of 1309561 is 1659031.

It is a cyclic number.

It is not a de Polignac number, because 1309561 - 2¹ = 1309559 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 (1309501) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8715 + ... + 8863.

It is an arithmetic number, because the mean of its divisors is an integer number (97200).

2^1309561 is an apocalyptic number.

1309561 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1309561 is a deficient number, since it is larger than the sum of its proper divisors (245639).

1309561 is a wasteful number, since it uses less digits than its factorization.

1309561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 224.

The product of its (nonzero) digits is 810, while the sum is 25.

The square root of 1309561 is about 1144.3605201159. The cubic root of 1309561 is about 109.4061942045.

The spelling of 1309561 in words is "one million, three hundred nine thousand, five hundred sixty-one".