66440378 has 16 divisors (see below), whose sum is σ = 108291840. Its totient is φ = 30456000.

The previous prime is 66440371. The next prime is 66440383. The reversal of 66440378 is 87304466.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (38).

It is not an unprimeable number, because it can be changed into a prime (66440371) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 27023 + ... + 29378.

It is an arithmetic number, because the mean of its divisors is an integer number (6768240).

Almost surely, 2^66440378 is an apocalyptic number.

66440378 is a deficient number, since it is larger than the sum of its proper divisors (41851462).

66440378 is a wasteful number, since it uses less digits than its factorization.

66440378 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 56453.

The product of its (nonzero) digits is 96768, while the sum is 38.

The square root of 66440378 is about 8151.0967360227. The cubic root of 66440378 is about 405.0208351828.

The spelling of 66440378 in words is "sixty-six million, four hundred forty thousand, three hundred seventy-eight".