66459978 has 48 divisors (see below), whose sum is σ = 155990016. Its totient is φ = 20328480.

The previous prime is 66459973. The next prime is 66460013. The reversal of 66459978 is 87995466.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66459973) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 43951 + ... + 45437.

It is an arithmetic number, because the mean of its divisors is an integer number (3249792).

Almost surely, 2^66459978 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66459978, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (77995008).

66459978 is an abundant number, since it is smaller than the sum of its proper divisors (89530038).

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

66459978 is a wasteful number, since it uses less digits than its factorization.

66459978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1699 (or 1696 counting only the distinct ones).

The product of its digits is 3265920, while the sum is 54.

The square root of 66459978 is about 8152.2989395630. The cubic root of 66459978 is about 405.0606584956.

The spelling of 66459978 in words is "sixty-six million, four hundred fifty-nine thousand, nine hundred seventy-eight".