66378624 has 64 divisors (see below), whose sum is σ = 189895440. Its totient is φ = 20422656.

The previous prime is 66378623. The next prime is 66378643. The reversal of 66378624 is 42687366.

It is a tau number, because it is divible by the number of its divisors (64).

It is a super-2 number, since 2×66378624² = 8812243448266752, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66378623) 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, 1657 + ... + 11640.

Almost surely, 2^66378624 is an apocalyptic number.

66378624 is a gapful number since it is divisible by the number (64) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66378624, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (94947720).

66378624 is an abundant number, since it is smaller than the sum of its proper divisors (123516816).

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

66378624 is a wasteful number, since it uses less digits than its factorization.

66378624 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13327 (or 13315 counting only the distinct ones).

The product of its digits is 290304, while the sum is 42.

The square root of 66378624 is about 8147.3077761921. The cubic root of 66378624 is about 404.8953120668.

The spelling of 66378624 in words is "sixty-six million, three hundred seventy-eight thousand, six hundred twenty-four".