66663880 has 16 divisors (see below), whose sum is σ = 149993820. Its totient is φ = 26665536.

The previous prime is 66663871. The next prime is 66663881. The reversal of 66663880 is 8836666.

It can be written as a sum of positive squares in 2 ways, for example, as 59013124 + 7650756 = 7682^2 + 2766^2 .

It is not an unprimeable number, because it can be changed into a prime (66663881) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 833259 + ... + 833338.

Almost surely, 2^66663880 is an apocalyptic number.

It is an amenable number.

66663880 is an abundant number, since it is smaller than the sum of its proper divisors (83329940).

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

66663880 is a wasteful number, since it uses less digits than its factorization.

66663880 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1666608 (or 1666604 counting only the distinct ones).

The product of its (nonzero) digits is 248832, while the sum is 43.

The square root of 66663880 is about 8164.7951597085. The cubic root of 66663880 is about 405.4744832697.

It can be divided in two parts, 666 and 63880, that added together give a palindrome (64546).

The spelling of 66663880 in words is "sixty-six million, six hundred sixty-three thousand, eight hundred eighty".