66857439 has 16 divisors (see below), whose sum is σ = 98144640. Its totient is φ = 40145760.

The previous prime is 66857431. The next prime is 66857459. The reversal of 66857439 is 93475866.

It is not a de Polignac number, because 66857439 - 2³ = 66857431 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66857431) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5697 + ... + 12890.

It is an arithmetic number, because the mean of its divisors is an integer number (6134040).

Almost surely, 2^66857439 is an apocalyptic number.

66857439 is a deficient number, since it is larger than the sum of its proper divisors (31287201).

66857439 is a wasteful number, since it uses less digits than its factorization.

66857439 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18710.

The product of its digits is 1088640, while the sum is 48.

The square root of 66857439 is about 8176.6398355315. The cubic root of 66857439 is about 405.8665366522.

The spelling of 66857439 in words is "sixty-six million, eight hundred fifty-seven thousand, four hundred thirty-nine".