1561289 has 4 divisors (see below), whose sum is σ = 1603524. Its totient is φ = 1519056.

The previous prime is 1561279. The next prime is 1561303. The reversal of 1561289 is 9821651.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 765625 + 795664 = 875^2 + 892^2 .

It is a cyclic number.

It is not a de Polignac number, because 1561289 - 2²⁰ = 512713 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1561279) 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, 21062 + ... + 21135.

It is an arithmetic number, because the mean of its divisors is an integer number (400881).

2^1561289 is an apocalyptic number.

It is an amenable number.

1561289 is a deficient number, since it is larger than the sum of its proper divisors (42235).

1561289 is an equidigital number, since it uses as much as digits as its factorization.

1561289 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42234.

The product of its digits is 4320, while the sum is 32.

The square root of 1561289 is about 1249.5155061063. The cubic root of 1561289 is about 116.0097346171.

The spelling of 1561289 in words is "one million, five hundred sixty-one thousand, two hundred eighty-nine".