66402005 has 4 divisors (see below), whose sum is σ = 79682412. Its totient is φ = 53121600.

The previous prime is 66401957. The next prime is 66402043. The reversal of 66402005 is 50020466.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 50020466 = 2 ⋅25010233.

It can be written as a sum of positive squares in 2 ways, for example, as 13490929 + 52911076 = 3673^2 + 7274^2 .

It is not a de Polignac number, because 66402005 - 2²⁰ = 65353429 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6640196 + ... + 6640205.

It is an arithmetic number, because the mean of its divisors is an integer number (19920603).

Almost surely, 2^66402005 is an apocalyptic number.

It is an amenable number.

66402005 is a deficient number, since it is larger than the sum of its proper divisors (13280407).

66402005 is a wasteful number, since it uses less digits than its factorization.

66402005 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13280406.

The product of its (nonzero) digits is 1440, while the sum is 23.

The square root of 66402005 is about 8148.7425410305. The cubic root of 66402005 is about 404.9428461745.

The spelling of 66402005 in words is "sixty-six million, four hundred two thousand, five".