66013820 has 12 divisors (see below), whose sum is σ = 138629064. Its totient is φ = 26405520.

The previous prime is 66013819. The next prime is 66013837. The reversal of 66013820 is 2831066.

It is a self number, because there is not a number n which added to its sum of digits gives 66013820.

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 3 ways as a sum of consecutive naturals, for example, 1650326 + ... + 1650365.

It is an arithmetic number, because the mean of its divisors is an integer number (11552422).

Almost surely, 2^66013820 is an apocalyptic number.

It is an amenable number.

66013820 is an abundant number, since it is smaller than the sum of its proper divisors (72615244).

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

66013820 is a wasteful number, since it uses less digits than its factorization.

66013820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3300700 (or 3300698 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 26.

The square root of 66013820 is about 8124.8889223176. Note that the first 3 decimals coincide. The cubic root of 66013820 is about 404.1522071326.

Adding to 66013820 its reverse (2831066), we get a palindrome (68844886).

The spelling of 66013820 in words is "sixty-six million, thirteen thousand, eight hundred twenty".