66394656 has 144 divisors (see below), whose sum is σ = 203793408. Its totient is φ = 20428800.

The previous prime is 66394651. The next prime is 66394667. The reversal of 66394656 is 65649366.

66394656 is a `hidden beast` number, since 6 + 639 + 4 + 6 + 5 + 6 = 666.

It is a tau number, because it is divible by the number of its divisors (144).

It is not an unprimeable number, because it can be changed into a prime (66394651) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 347521 + ... + 347711.

It is an arithmetic number, because the mean of its divisors is an integer number (1415232).

Almost surely, 2^66394656 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 66394656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (101896704).

66394656 is an abundant number, since it is smaller than the sum of its proper divisors (137398752).

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

66394656 is a wasteful number, since it uses less digits than its factorization.

66394656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 295 (or 284 counting only the distinct ones).

The product of its digits is 699840, while the sum is 45.

The square root of 66394656 is about 8148.2916000840. The cubic root of 66394656 is about 404.9279066920.

The spelling of 66394656 in words is "sixty-six million, three hundred ninety-four thousand, six hundred fifty-six".