1540542517561 has 2 divisors, whose sum is σ = 1540542517562. Its totient is φ = 1540542517560.

The previous prime is 1540542517453. The next prime is 1540542517571. The reversal of 1540542517561 is 1657152450451.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1510342681600 + 30199835961 = 1228960^2 + 173781^2 .

It is a cyclic number.

It is not a de Polignac number, because 1540542517561 - 2¹⁷ = 1540542386489 is a prime.

It is not a weakly prime, because it can be changed into another prime (1540542517571) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 770271258780 + 770271258781.

It is an arithmetic number, because the mean of its divisors is an integer number (770271258781).

Almost surely, 2^{1540542517561} is an apocalyptic number.

It is an amenable number.

1540542517561 is a deficient number, since it is larger than the sum of its proper divisors (1).

1540542517561 is an equidigital number, since it uses as much as digits as its factorization.

1540542517561 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 840000, while the sum is 46.

The spelling of 1540542517561 in words is "one trillion, five hundred forty billion, five hundred forty-two million, five hundred seventeen thousand, five hundred sixty-one".