66440388 has 24 divisors (see below), whose sum is σ = 177174592. Its totient is φ = 18982944.

The previous prime is 66440383. The next prime is 66440393. The reversal of 66440388 is 88304466.

It is an interprime number because it is at equal distance from previous prime (66440383) and next prime (66440393).

It is not an unprimeable number, because it can be changed into a prime (66440383) 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, 395395 + ... + 395562.

Almost surely, 2^66440388 is an apocalyptic number.

It is an amenable number.

66440388 is an abundant number, since it is smaller than the sum of its proper divisors (110734204).

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

66440388 is a wasteful number, since it uses less digits than its factorization.

66440388 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 790971 (or 790969 counting only the distinct ones).

The product of its (nonzero) digits is 110592, while the sum is 39.

The square root of 66440388 is about 8151.0973494371. The cubic root of 66440388 is about 405.0208555028.

The spelling of 66440388 in words is "sixty-six million, four hundred forty thousand, three hundred eighty-eight".