19566405632449 has 9 divisors (see below), whose sum is σ = 21187353574089. Its totient is φ = 18061244426160.

The previous prime is 19566405632447. The next prime is 19566405632479. The reversal of 19566405632449 is 94423650466591.

The square root of 19566405632449 is 4423393.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 10222183756225 + 9344221876224 = 3197215^2 + 3056832^2 .

It is not a de Polignac number, because 19566405632449 - 2¹ = 19566405632447 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19566405632447) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 57333979 + ... + 57674239.

It is an arithmetic number, because the mean of its divisors is an integer number (2354150397121).

Almost surely, 2^{19566405632449} is an apocalyptic number.

19566405632449 is the 4423393-rd square number.

19566405632449 is the 2211697-th centered octagonal number.

It is an amenable number.

19566405632449 is a deficient number, since it is larger than the sum of its proper divisors (1620947941640).

19566405632449 is an frugal number, since it uses more digits than its factorization.

19566405632449 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 680548 (or 340274 counting only the distinct ones).

The product of its (nonzero) digits is 167961600, while the sum is 64.

The spelling of 19566405632449 in words is "nineteen trillion, five hundred sixty-six billion, four hundred five million, six hundred thirty-two thousand, four hundred forty-nine".