6665066405 has 4 divisors (see below), whose sum is σ = 7998079692. Its totient is φ = 5332053120.

The previous prime is 6665066383. The next prime is 6665066407. The reversal of 6665066405 is 5046605666.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5046605666 = 2 ⋅2523302833.

It can be written as a sum of positive squares in 2 ways, for example, as 4077716449 + 2587349956 = 63857^2 + 50866^2 .

It is not a de Polignac number, because 6665066405 - 2¹² = 6665062309 is a prime.

It is a super-2 number, since 2×6665066405² = 88846220366119248050, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6665066407) by changing a digit.

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, 666506636 + ... + 666506645.

It is an arithmetic number, because the mean of its divisors is an integer number (1999519923).

Almost surely, 2^6665066405 is an apocalyptic number.

It is an amenable number.

6665066405 is a deficient number, since it is larger than the sum of its proper divisors (1333013287).

6665066405 is a wasteful number, since it uses less digits than its factorization.

6665066405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1333013286.

The product of its (nonzero) digits is 777600, while the sum is 44.

The square root of 6665066405 is about 81639.8579432865. The cubic root of 6665066405 is about 1881.9214553229.

The spelling of 6665066405 in words is "six billion, six hundred sixty-five million, sixty-six thousand, four hundred five".