1561251143 has 2 divisors, whose sum is σ = 1561251144. Its totient is φ = 1561251142.

The previous prime is 1561251121. The next prime is 1561251161. The reversal of 1561251143 is 3411521651.

It is a strong prime.

It is an emirp because it is prime and its reverse (3411521651) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1561251143 - 2⁶ = 1561251079 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1561251113) 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 as a sum of consecutive naturals, namely, 780625571 + 780625572.

It is an arithmetic number, because the mean of its divisors is an integer number (780625572).

Almost surely, 2^1561251143 is an apocalyptic number.

1561251143 is a deficient number, since it is larger than the sum of its proper divisors (1).

1561251143 is an equidigital number, since it uses as much as digits as its factorization.

1561251143 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3600, while the sum is 29.

The square root of 1561251143 is about 39512.6706639782. The cubic root of 1561251143 is about 1160.0879696960.

Adding to 1561251143 its reverse (3411521651), we get a palindrome (4972772794).

The spelling of 1561251143 in words is "one billion, five hundred sixty-one million, two hundred fifty-one thousand, one hundred forty-three".