1561685141 has 2 divisors, whose sum is σ = 1561685142. Its totient is φ = 1561685140.

The previous prime is 1561685117. The next prime is 1561685143. The reversal of 1561685141 is 1415861651.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 836944900 + 724740241 = 28930^2 + 26921^2 .

It is a cyclic number.

It is not a de Polignac number, because 1561685141 - 2⁶ = 1561685077 is a prime.

Together with 1561685143, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 1561685095 and 1561685104.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1561685143) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 780842570 + 780842571.

It is an arithmetic number, because the mean of its divisors is an integer number (780842571).

Almost surely, 2^1561685141 is an apocalyptic number.

It is an amenable number.

1561685141 is a deficient number, since it is larger than the sum of its proper divisors (1).

1561685141 is an equidigital number, since it uses as much as digits as its factorization.

1561685141 is an evil number, because the sum of its binary digits is even.

The product of its digits is 28800, while the sum is 38.

The square root of 1561685141 is about 39518.1621662749. The cubic root of 1561685141 is about 1160.1954538369.

The spelling of 1561685141 in words is "one billion, five hundred sixty-one million, six hundred eighty-five thousand, one hundred forty-one".