66896720 has 80 divisors (see below), whose sum is σ = 178649280. Its totient is φ = 23040000.

The previous prime is 66896699. The next prime is 66896723. The reversal of 66896720 is 2769866.

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

It is a super-2 number, since 2×66896720² = 8950342293516800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (44).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66896723) 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, 14720 + ... + 18720.

It is an arithmetic number, because the mean of its divisors is an integer number (2233116).

Almost surely, 2^66896720 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 66896720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (89324640).

66896720 is an abundant number, since it is smaller than the sum of its proper divisors (111752560).

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

66896720 is a wasteful number, since it uses less digits than its factorization.

66896720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4044 (or 4038 counting only the distinct ones).

The product of its (nonzero) digits is 217728, while the sum is 44.

The square root of 66896720 is about 8179.0415086366. The cubic root of 66896720 is about 405.9460078492.

The spelling of 66896720 in words is "sixty-six million, eight hundred ninety-six thousand, seven hundred twenty".