1561560765 has 32 divisors (see below), whose sum is σ = 2569104000. Its totient is φ = 809351424.

The previous prime is 1561560751. The next prime is 1561560769. The reversal of 1561560765 is 5670651651.

It is not a de Polignac number, because 1561560765 - 2¹⁸ = 1561298621 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1561560769) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 831007 + ... + 832883.

It is an arithmetic number, because the mean of its divisors is an integer number (80284500).

Almost surely, 2^1561560765 is an apocalyptic number.

1561560765 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1561560765 is a deficient number, since it is larger than the sum of its proper divisors (1007543235).

1561560765 is a wasteful number, since it uses less digits than its factorization.

1561560765 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3421.

The product of its (nonzero) digits is 189000, while the sum is 42.

The square root of 1561560765 is about 39516.5884787642. The cubic root of 1561560765 is about 1160.1646528564.

The spelling of 1561560765 in words is "one billion, five hundred sixty-one million, five hundred sixty thousand, seven hundred sixty-five".