66055821 has 16 divisors (see below), whose sum is σ = 96870144. Its totient is φ = 39783744.

The previous prime is 66055819. The next prime is 66055849. The reversal of 66055821 is 12855066.

It is not a de Polignac number, because 66055821 - 2¹ = 66055819 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66055811) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 16186 + ... + 19851.

It is an arithmetic number, because the mean of its divisors is an integer number (6054384).

Almost surely, 2^66055821 is an apocalyptic number.

It is an amenable number.

66055821 is a deficient number, since it is larger than the sum of its proper divisors (30814323).

66055821 is a wasteful number, since it uses less digits than its factorization.

66055821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36100.

The product of its (nonzero) digits is 14400, while the sum is 33.

The square root of 66055821 is about 8127.4732235794. The cubic root of 66055821 is about 404.2379023101.

The spelling of 66055821 in words is "sixty-six million, fifty-five thousand, eight hundred twenty-one".