1561340203 has 4 divisors (see below), whose sum is σ = 1611706048. Its totient is φ = 1510974360.

The previous prime is 1561340177. The next prime is 1561340233. The reversal of 1561340203 is 3020431651.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 3020431651 = 7349 ⋅410999.

It is a cyclic number.

It is not a de Polignac number, because 1561340203 - 2²⁵ = 1527785771 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1561340233) 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 3 ways as a sum of consecutive naturals, for example, 25182876 + ... + 25182937.

It is an arithmetic number, because the mean of its divisors is an integer number (402926512).

Almost surely, 2^1561340203 is an apocalyptic number.

1561340203 is a deficient number, since it is larger than the sum of its proper divisors (50365845).

1561340203 is an equidigital number, since it uses as much as digits as its factorization.

1561340203 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 50365844.

The product of its (nonzero) digits is 2160, while the sum is 25.

The square root of 1561340203 is about 39513.7976281703. The cubic root of 1561340203 is about 1160.1100279601.

Adding to 1561340203 its reverse (3020431651), we get a palindrome (4581771854).

The spelling of 1561340203 in words is "one billion, five hundred sixty-one million, three hundred forty thousand, two hundred three".