66784880 has 20 divisors (see below), whose sum is σ = 155275032. Its totient is φ = 26713920.

The previous prime is 66784843. The next prime is 66784901. The reversal of 66784880 is 8848766.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (20).

It is a super-2 number, since 2×66784880² = 8920440393228800, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 417326 + ... + 417485.

Almost surely, 2^66784880 is an apocalyptic number.

It is an amenable number.

66784880 is an abundant number, since it is smaller than the sum of its proper divisors (88490152).

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

66784880 is a wasteful number, since it uses less digits than its factorization.

66784880 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 834824 (or 834818 counting only the distinct ones).

The product of its (nonzero) digits is 516096, while the sum is 47.

The square root of 66784880 is about 8172.2016617311. The cubic root of 66784880 is about 405.7196573098.

The spelling of 66784880 in words is "sixty-six million, seven hundred eighty-four thousand, eight hundred eighty".