66681530 has 16 divisors (see below), whose sum is σ = 121547520. Its totient is φ = 26334672.

The previous prime is 66681521. The next prime is 66681533. The reversal of 66681530 is 3518666.

66681530 = 408² + 409² + ... + 644².

It is not an unprimeable number, because it can be changed into a prime (66681533) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 41414 + ... + 42993.

It is an arithmetic number, because the mean of its divisors is an integer number (7596720).

Almost surely, 2^66681530 is an apocalyptic number.

66681530 is a deficient number, since it is larger than the sum of its proper divisors (54865990).

66681530 is a wasteful number, since it uses less digits than its factorization.

66681530 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 84493.

The product of its (nonzero) digits is 25920, while the sum is 35.

The square root of 66681530 is about 8165.8759481148. The cubic root of 66681530 is about 405.5102647309.

The spelling of 66681530 in words is "sixty-six million, six hundred eighty-one thousand, five hundred thirty".