66378720 has 48 divisors (see below), whose sum is σ = 209094480. Its totient is φ = 17700864.

The previous prime is 66378691. The next prime is 66378743. The reversal of 66378720 is 2787366.

It is a tau number, because it is divible by the number of its divisors (48).

It is a super-2 number, since 2×66378720² = 8812268937676800, 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 7 ways as a sum of consecutive naturals, for example, 68665 + ... + 69624.

It is an arithmetic number, because the mean of its divisors is an integer number (4356135).

Almost surely, 2^66378720 is an apocalyptic number.

66378720 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

66378720 is an abundant number, since it is smaller than the sum of its proper divisors (142715760).

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

66378720 is a wasteful number, since it uses less digits than its factorization.

66378720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 138307 (or 138299 counting only the distinct ones).

The product of its (nonzero) digits is 84672, while the sum is 39.

The square root of 66378720 is about 8147.3136677067. The cubic root of 66378720 is about 404.8955072598.

The spelling of 66378720 in words is "sixty-six million, three hundred seventy-eight thousand, seven hundred twenty".