1561244249 has 4 divisors (see below), whose sum is σ = 1653082164. Its totient is φ = 1469406336.

The previous prime is 1561244221. The next prime is 1561244257. The reversal of 1561244249 is 9424421651.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 9424421651 = 4703 ⋅2003917.

It can be written as a sum of positive squares in 2 ways, for example, as 1446433024 + 114811225 = 38032^2 + 10715^2 .

It is a cyclic number.

It is not a de Polignac number, because 1561244249 - 2²⁸ = 1292808793 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1561244219) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 45918932 + ... + 45918965.

It is an arithmetic number, because the mean of its divisors is an integer number (413270541).

Almost surely, 2^1561244249 is an apocalyptic number.

It is an amenable number.

1561244249 is a deficient number, since it is larger than the sum of its proper divisors (91837915).

1561244249 is an equidigital number, since it uses as much as digits as its factorization.

1561244249 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 91837914.

The product of its digits is 69120, while the sum is 38.

The square root of 1561244249 is about 39512.5834260429. The cubic root of 1561244249 is about 1160.0862621641.

The spelling of 1561244249 in words is "one billion, five hundred sixty-one million, two hundred forty-four thousand, two hundred forty-nine".