66139857 has 36 divisors (see below), whose sum is σ = 113533056. Its totient is φ = 36978480.

The previous prime is 66139823. The next prime is 66139859. The reversal of 66139857 is 75893166.

It is a happy number.

It is not a de Polignac number, because 66139857 - 2⁷ = 66139729 is a prime.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66139859) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 19132 + ... + 22322.

It is an arithmetic number, because the mean of its divisors is an integer number (3153696).

Almost surely, 2^66139857 is an apocalyptic number.

It is an amenable number.

66139857 is a deficient number, since it is larger than the sum of its proper divisors (47393199).

66139857 is a wasteful number, since it uses less digits than its factorization.

66139857 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3258 (or 3248 counting only the distinct ones).

The product of its digits is 272160, while the sum is 45.

The square root of 66139857 is about 8132.6414528122. The cubic root of 66139857 is about 404.4092530469.

The spelling of 66139857 in words is "sixty-six million, one hundred thirty-nine thousand, eight hundred fifty-seven".