66481640 has 16 divisors (see below), whose sum is σ = 149583780. Its totient is φ = 26592640.

The previous prime is 66481633. The next prime is 66481691. The reversal of 66481640 is 4618466.

It can be written as a sum of positive squares in 2 ways, for example, as 62694724 + 3786916 = 7918^2 + 1946^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 66481640.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 830981 + ... + 831060.

Almost surely, 2^66481640 is an apocalyptic number.

It is an amenable number.

66481640 is an abundant number, since it is smaller than the sum of its proper divisors (83102140).

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

66481640 is a wasteful number, since it uses less digits than its factorization.

66481640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1662052 (or 1662048 counting only the distinct ones).

The product of its (nonzero) digits is 27648, while the sum is 35.

The square root of 66481640 is about 8153.6274136117. The cubic root of 66481640 is about 405.1046622761.

The spelling of 66481640 in words is "sixty-six million, four hundred eighty-one thousand, six hundred forty".