66561876 has 36 divisors (see below), whose sum is σ = 169396500. Its totient is φ = 22036608.

The previous prime is 66561863. The next prime is 66561899. The reversal of 66561876 is 67816566.

66561876 is a `hidden beast` number, since 6 + 6 + 561 + 87 + 6 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 4309776 + 62252100 = 2076^2 + 7890^2 .

It is a tau number, because it is divible by the number of its divisors (36).

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 11 ways as a sum of consecutive naturals, for example, 841 + ... + 11568.

Almost surely, 2^66561876 is an apocalyptic number.

It is an amenable number.

66561876 is an abundant number, since it is smaller than the sum of its proper divisors (102834624).

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

66561876 is a wasteful number, since it uses less digits than its factorization.

66561876 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12568 (or 12563 counting only the distinct ones).

The product of its digits is 362880, while the sum is 45.

The square root of 66561876 is about 8158.5461940226. The cubic root of 66561876 is about 405.2675689583.

The spelling of 66561876 in words is "sixty-six million, five hundred sixty-one thousand, eight hundred seventy-six".