66246640 has 40 divisors (see below), whose sum is σ = 154365120. Its totient is φ = 26439936.

The previous prime is 66246619. The next prime is 66246667. The reversal of 66246640 is 4664266.

It is a tau number, because it is divible by the number of its divisors (40).

It is a super-2 number, since 2×66246640² = 8777234622579200, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 66246596 and 66246605.

It is a congruent number.

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 7 ways as a sum of consecutive naturals, for example, 63241 + ... + 64279.

It is an arithmetic number, because the mean of its divisors is an integer number (3859128).

Almost surely, 2^66246640 is an apocalyptic number.

It is an amenable number.

66246640 is an abundant number, since it is smaller than the sum of its proper divisors (88118480).

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

66246640 is a wasteful number, since it uses less digits than its factorization.

66246640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1849 (or 1843 counting only the distinct ones).

The product of its (nonzero) digits is 41472, while the sum is 34.

The square root of 66246640 is about 8139.2038922735. The cubic root of 66246640 is about 404.6267760142.

The spelling of 66246640 in words is "sixty-six million, two hundred forty-six thousand, six hundred forty".