1561773797 has 4 divisors (see below), whose sum is σ = 1563441516. Its totient is φ = 1560106080.

The previous prime is 1561773767. The next prime is 1561773827. The reversal of 1561773797 is 7973771651.

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

It is an interprime number because it is at equal distance from previous prime (1561773767) and next prime (1561773827).

It can be written as a sum of positive squares in 2 ways, for example, as 948270436 + 613503361 = 30794^2 + 24769^2 .

It is a cyclic number.

It is not a de Polignac number, because 1561773797 - 2²⁴ = 1544996581 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1561773757) 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 3 ways as a sum of consecutive naturals, for example, 832454 + ... + 834327.

It is an arithmetic number, because the mean of its divisors is an integer number (390860379).

Almost surely, 2^1561773797 is an apocalyptic number.

It is an amenable number.

1561773797 is a deficient number, since it is larger than the sum of its proper divisors (1667719).

1561773797 is an equidigital number, since it uses as much as digits as its factorization.

1561773797 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1667718.

The product of its digits is 1944810, while the sum is 53.

The square root of 1561773797 is about 39519.2838624386. The cubic root of 1561773797 is about 1160.2174079725.

The spelling of 1561773797 in words is "one billion, five hundred sixty-one million, seven hundred seventy-three thousand, seven hundred ninety-seven".