1371845561 has 2 divisors, whose sum is σ = 1371845562. Its totient is φ = 1371845560.

The previous prime is 1371845483. The next prime is 1371845597. The reversal of 1371845561 is 1655481731.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1299169936 + 72675625 = 36044^2 + 8525^2 .

It is a cyclic number.

It is not a de Polignac number, because 1371845561 - 2¹⁴ = 1371829177 is a prime.

It is not a weakly prime, because it can be changed into another prime (1371845161) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 685922780 + 685922781.

It is an arithmetic number, because the mean of its divisors is an integer number (685922781).

Almost surely, 2^1371845561 is an apocalyptic number.

It is an amenable number.

1371845561 is a deficient number, since it is larger than the sum of its proper divisors (1).

1371845561 is an equidigital number, since it uses as much as digits as its factorization.

1371845561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 100800, while the sum is 41.

The square root of 1371845561 is about 37038.4335656896. The cubic root of 1371845561 is about 1111.1390415086.

The spelling of 1371845561 in words is "one billion, three hundred seventy-one million, eight hundred forty-five thousand, five hundred sixty-one".