66904720 has 40 divisors (see below), whose sum is σ = 157757760. Its totient is φ = 26382720.

The previous prime is 66904703. The next prime is 66904729. The reversal of 66904720 is 2740966.

It is a tau number, because it is divible by the number of its divisors (40).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66904729) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 210 + ... + 11569.

It is an arithmetic number, because the mean of its divisors is an integer number (3943944).

Almost surely, 2^66904720 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 66904720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (78878880).

66904720 is an abundant number, since it is smaller than the sum of its proper divisors (90853040).

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

66904720 is a wasteful number, since it uses less digits than its factorization.

66904720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11863 (or 11857 counting only the distinct ones).

The product of its (nonzero) digits is 18144, while the sum is 34.

The square root of 66904720 is about 8179.5305488763. The cubic root of 66904720 is about 405.9621892037.

The spelling of 66904720 in words is "sixty-six million, nine hundred four thousand, seven hundred twenty".