1645571361617 has 2 divisors, whose sum is σ = 1645571361618. Its totient is φ = 1645571361616.

The previous prime is 1645571361611. The next prime is 1645571361667. The reversal of 1645571361617 is 7161631755461.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1308642193681 + 336929167936 = 1143959^2 + 580456^2 .

It is a cyclic number.

It is not a de Polignac number, because 1645571361617 - 2⁴⁰ = 546059733841 is a prime.

It is not a weakly prime, because it can be changed into another prime (1645571361611) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 822785680808 + 822785680809.

It is an arithmetic number, because the mean of its divisors is an integer number (822785680809).

Almost surely, 2^{1645571361617} is an apocalyptic number.

It is an amenable number.

1645571361617 is a deficient number, since it is larger than the sum of its proper divisors (1).

1645571361617 is an equidigital number, since it uses as much as digits as its factorization.

1645571361617 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3175200, while the sum is 53.

The spelling of 1645571361617 in words is "one trillion, six hundred forty-five billion, five hundred seventy-one million, three hundred sixty-one thousand, six hundred seventeen".