66581764 has 12 divisors (see below), whose sum is σ = 116866204. Its totient is φ = 33191424.

The previous prime is 66581743. The next prime is 66581773. The reversal of 66581764 is 46718566.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 36966400 + 29615364 = 6080^2 + 5442^2 .

It is a hoax number, since the sum of its digits (43) coincides with the sum of the digits of its distinct prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 66581764.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 23349 + ... + 26044.

Almost surely, 2^66581764 is an apocalyptic number.

It is an amenable number.

66581764 is a deficient number, since it is larger than the sum of its proper divisors (50284440).

66581764 is a wasteful number, since it uses less digits than its factorization.

66581764 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 49734 (or 49732 counting only the distinct ones).

The product of its digits is 241920, while the sum is 43.

The square root of 66581764 is about 8159.7649475950. The cubic root of 66581764 is about 405.3079281914.

The spelling of 66581764 in words is "sixty-six million, five hundred eighty-one thousand, seven hundred sixty-four".