66299555169 has 9 divisors (see below), whose sum is σ = 95767139923. Its totient is φ = 44199188472.

The previous prime is 66299555089. The next prime is 66299555171. The reversal of 66299555169 is 96155599266.

The square root of 66299555169 is 257487.

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

66299555169 is a `hidden beast` number, since 6 + 6 + 29 + 95 + 5 + 516 + 9 = 666.

It can be written as a sum of positive squares in only one way, i.e., 1671746769 + 64627808400 = 40887^2 + 254220^2 .

It is a tau number, because it is divible by the number of its divisors (9).

It is not a de Polignac number, because 66299555169 - 2²⁹ = 65762684257 is a prime.

It is a super-2 number, since 2×66299555169² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66299557169) 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, 729547 + ... + 815375.

Almost surely, 2^66299555169 is an apocalyptic number.

66299555169 is the 257487-th square number.

66299555169 is the 128744-th centered octagonal number.

It is an amenable number.

66299555169 is a deficient number, since it is larger than the sum of its proper divisors (29467584754).

66299555169 is an frugal number, since it uses more digits than its factorization.

66299555169 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 171664 (or 85832 counting only the distinct ones).

The product of its digits is 39366000, while the sum is 63.

The spelling of 66299555169 in words is "sixty-six billion, two hundred ninety-nine million, five hundred fifty-five thousand, one hundred sixty-nine".