1561205 has 4 divisors (see below), whose sum is σ = 1873452. Its totient is φ = 1248960.

The previous prime is 1561193. The next prime is 1561213. The reversal of 1561205 is 5021651.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5021651 = 467 ⋅10753.

It can be written as a sum of positive squares in 2 ways, for example, as 770884 + 790321 = 878^2 + 889^2 .

It is not a de Polignac number, because 1561205 - 2¹² = 1557109 is a prime.

It is a super-2 number, since 2×1561205² = 4874722104050, which contains 22 as substring.

It is a Duffinian 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, 156116 + ... + 156125.

It is an arithmetic number, because the mean of its divisors is an integer number (468363).

2^1561205 is an apocalyptic number.

It is an amenable number.

1561205 is a deficient number, since it is larger than the sum of its proper divisors (312247).

1561205 is an equidigital number, since it uses as much as digits as its factorization.

1561205 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 312246.

The product of its (nonzero) digits is 300, while the sum is 20.

The square root of 1561205 is about 1249.4818926259. The cubic root of 1561205 is about 116.0076540728.

Adding to 1561205 its reverse (5021651), we get a palindrome (6582856).

The spelling of 1561205 in words is "one million, five hundred sixty-one thousand, two hundred five".