1561685143 has 2 divisors, whose sum is σ = 1561685144. Its totient is φ = 1561685142.

The previous prime is 1561685141. The next prime is 1561685173. The reversal of 1561685143 is 3415861651.

It is a weak prime.

It is an emirp because it is prime and its reverse (3415861651) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1561685143 - 2¹ = 1561685141 is a prime.

Together with 1561685141, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 1561685096 and 1561685105.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1561685141) 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, 780842571 + 780842572.

It is an arithmetic number, because the mean of its divisors is an integer number (780842572).

Almost surely, 2^1561685143 is an apocalyptic number.

1561685143 is a deficient number, since it is larger than the sum of its proper divisors (1).

1561685143 is an equidigital number, since it uses as much as digits as its factorization.

1561685143 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 86400, while the sum is 40.

The square root of 1561685143 is about 39518.1621915797. The cubic root of 1561685143 is about 1160.1954543322.

The spelling of 1561685143 in words is "one billion, five hundred sixty-one million, six hundred eighty-five thousand, one hundred forty-three".