1561045 has 4 divisors (see below), whose sum is σ = 1873260. Its totient is φ = 1248832.

The previous prime is 1561039. The next prime is 1561069. The reversal of 1561045 is 5401651.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5401651 = 1447 ⋅3733.

It can be written as a sum of positive squares in 2 ways, for example, as 1052676 + 508369 = 1026^2 + 713^2 .

It is a cyclic number.

It is not a de Polignac number, because 1561045 - 2³ = 1561037 is a prime.

It is a super-2 number, since 2×1561045² = 4873722984050, which contains 22 as substring.

It is a Smith number, since the sum of its digits (22) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 156100 + ... + 156109.

It is an arithmetic number, because the mean of its divisors is an integer number (468315).

2^1561045 is an apocalyptic number.

It is an amenable number.

1561045 is a deficient number, since it is larger than the sum of its proper divisors (312215).

1561045 is an equidigital number, since it uses as much as digits as its factorization.

1561045 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 312214.

The product of its (nonzero) digits is 600, while the sum is 22.

The square root of 1561045 is about 1249.4178644473. The cubic root of 1561045 is about 116.0036909250.

Adding to 1561045 its reverse (5401651), we get a palindrome (6962696).

Subtracting 1561045 from its reverse (5401651), we obtain a triangular number (3840606 = T₂₇₇₁).

The spelling of 1561045 in words is "one million, five hundred sixty-one thousand, forty-five".