66646672605 has 12 divisors (see below), whose sum is σ = 115520899260. Its totient is φ = 35544892032.

The previous prime is 66646672601. The next prime is 66646672607. The reversal of 66646672605 is 50627664666.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 14998655961 + 51648016644 = 122469^2 + 227262^2 .

It is not a de Polignac number, because 66646672605 - 2² = 66646672601 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66646672601) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 740518540 + ... + 740518629.

It is an arithmetic number, because the mean of its divisors is an integer number (9626741605).

Almost surely, 2^66646672605 is an apocalyptic number.

It is an amenable number.

66646672605 is a deficient number, since it is larger than the sum of its proper divisors (48874226655).

66646672605 is a wasteful number, since it uses less digits than its factorization.

66646672605 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1481037180 (or 1481037177 counting only the distinct ones).

The product of its (nonzero) digits is 13063680, while the sum is 54.

The spelling of 66646672605 in words is "sixty-six billion, six hundred forty-six million, six hundred seventy-two thousand, six hundred five".