66136720 has 80 divisors (see below), whose sum is σ = 174363840. Its totient is φ = 23127552.

The previous prime is 66136717. The next prime is 66136727. The reversal of 66136720 is 2763166.

It is a tau number, because it is divible by the number of its divisors (80).

It is not an unprimeable number, because it can be changed into a prime (66136727) 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, 18087 + ... + 21433.

It is an arithmetic number, because the mean of its divisors is an integer number (2179548).

Almost surely, 2^66136720 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 66136720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (87181920).

66136720 is an abundant number, since it is smaller than the sum of its proper divisors (108227120).

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

66136720 is a wasteful number, since it uses less digits than its factorization.

66136720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3392 (or 3386 counting only the distinct ones).

The product of its (nonzero) digits is 9072, while the sum is 31.

The square root of 66136720 is about 8132.4485857582. The cubic root of 66136720 is about 404.4028592629.

Adding to 66136720 its reverse (2763166), we get a palindrome (68899886).

The spelling of 66136720 in words is "sixty-six million, one hundred thirty-six thousand, seven hundred twenty".