66439758 has 64 divisors (see below), whose sum is σ = 171048960. Its totient is φ = 16696800.

The previous prime is 66439733. The next prime is 66439759. The reversal of 66439758 is 85793466.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66439759) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 12003 + ... + 16641.

It is an arithmetic number, because the mean of its divisors is an integer number (2672640).

Almost surely, 2^66439758 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66439758, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (85524480).

66439758 is an abundant number, since it is smaller than the sum of its proper divisors (104609202).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

66439758 is a wasteful number, since it uses less digits than its factorization.

66439758 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4693.

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

The square root of 66439758 is about 8151.0587042420. The cubic root of 66439758 is about 405.0195753379.

The spelling of 66439758 in words is "sixty-six million, four hundred thirty-nine thousand, seven hundred fifty-eight".