66666637 has 8 divisors (see below), whose sum is σ = 69631200. Its totient is φ = 63763344.

The previous prime is 66666631. The next prime is 66666643. The reversal of 66666637 is 73666666.

66666637 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (66666631) and next prime (66666643).

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 66666637 - 2³ = 66666629 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66666631) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13087 + ... + 17452.

It is an arithmetic number, because the mean of its divisors is an integer number (8703900).

Almost surely, 2^66666637 is an apocalyptic number.

It is an amenable number.

66666637 is a deficient number, since it is larger than the sum of its proper divisors (2964563).

66666637 is a wasteful number, since it uses less digits than its factorization.

66666637 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30635.

The product of its digits is 979776, while the sum is 46.

The square root of 66666637 is about 8164.9639925722. The cubic root of 66666637 is about 405.4800728920.

It can be divided in two parts, 666666 and 37, that multiplied together give a palindrome (24666642).

The spelling of 66666637 in words is "sixty-six million, six hundred sixty-six thousand, six hundred thirty-seven".