1561500616541 has 2 divisors, whose sum is σ = 1561500616542. Its totient is φ = 1561500616540.

The previous prime is 1561500616523. The next prime is 1561500616591. The reversal of 1561500616541 is 1456160051651.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1464956805316 + 96543811225 = 1210354^2 + 310715^2 .

It is a cyclic number.

It is not a de Polignac number, because 1561500616541 - 2¹⁰ = 1561500615517 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1561500616591) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 780750308270 + 780750308271.

It is an arithmetic number, because the mean of its divisors is an integer number (780750308271).

Almost surely, 2^{1561500616541} is an apocalyptic number.

It is an amenable number.

1561500616541 is a deficient number, since it is larger than the sum of its proper divisors (1).

1561500616541 is an equidigital number, since it uses as much as digits as its factorization.

1561500616541 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 108000, while the sum is 41.

The spelling of 1561500616541 in words is "one trillion, five hundred sixty-one billion, five hundred million, six hundred sixteen thousand, five hundred forty-one".