1561539 has 32 divisors (see below), whose sum is σ = 2571264. Its totient is φ = 823680.

The previous prime is 1561537. The next prime is 1561541. The reversal of 1561539 is 9351651.

It is an interprime number because it is at equal distance from previous prime (1561537) and next prime (1561541).

It is not a de Polignac number, because 1561539 - 2¹ = 1561537 is a prime.

It is a Smith number, since the sum of its digits (30) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

1561539 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (1561537) by changing a digit.

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 31 ways as a sum of consecutive naturals, for example, 25569 + ... + 25629.

It is an arithmetic number, because the mean of its divisors is an integer number (80352).

2^1561539 is an apocalyptic number.

1561539 is a deficient number, since it is larger than the sum of its proper divisors (1009725).

1561539 is a wasteful number, since it uses less digits than its factorization.

1561539 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 147.

The product of its digits is 4050, while the sum is 30.

The square root of 1561539 is about 1249.6155408765. The cubic root of 1561539 is about 116.0159262715.

The spelling of 1561539 in words is "one million, five hundred sixty-one thousand, five hundred thirty-nine".