66711918 has 64 divisors (see below), whose sum is σ = 166989312. Its totient is φ = 17297280.

The previous prime is 66711917. The next prime is 66711943. The reversal of 66711918 is 81911766.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66711913) 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, 32305 + ... + 34307.

It is an arithmetic number, because the mean of its divisors is an integer number (2609208).

Almost surely, 2^66711918 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66711918, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (83494656).

66711918 is an abundant number, since it is smaller than the sum of its proper divisors (100277394).

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

66711918 is a wasteful number, since it uses less digits than its factorization.

66711918 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2089.

The product of its digits is 18144, while the sum is 39.

The square root of 66711918 is about 8167.7364061287. The cubic root of 66711918 is about 405.5718548720.

The spelling of 66711918 in words is "sixty-six million, seven hundred eleven thousand, nine hundred eighteen".