66639996 has 60 divisors (see below), whose sum is σ = 176243760. Its totient is φ = 21954240.

The previous prime is 66639977. The next prime is 66640003. The reversal of 66639996 is 69993666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 27681 + ... + 29991.

It is an arithmetic number, because the mean of its divisors is an integer number (2937396).

Almost surely, 2^66639996 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66639996, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (88121880).

66639996 is an abundant number, since it is smaller than the sum of its proper divisors (109603764).

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

66639996 is a wasteful number, since it uses less digits than its factorization.

66639996 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2416 (or 2405 counting only the distinct ones).

The product of its digits is 2834352, while the sum is 54.

The square root of 66639996 is about 8163.3324077854. The cubic root of 66639996 is about 405.4260536986.

The spelling of 66639996 in words is "sixty-six million, six hundred thirty-nine thousand, nine hundred ninety-six".