66572161 has 4 divisors (see below), whose sum is σ = 66633300. Its totient is φ = 66511024.

The previous prime is 66572141. The next prime is 66572171. The reversal of 66572161 is 16127566.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 36978561 + 29593600 = 6081^2 + 5440^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66572161 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66572111) by changing a digit.

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, 28906 + ... + 31123.

It is an arithmetic number, because the mean of its divisors is an integer number (16658325).

Almost surely, 2^66572161 is an apocalyptic number.

It is an amenable number.

66572161 is a deficient number, since it is larger than the sum of its proper divisors (61139).

66572161 is a wasteful number, since it uses less digits than its factorization.

66572161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 61138.

The product of its digits is 15120, while the sum is 34.

The square root of 66572161 is about 8159.1764903083. The cubic root of 66572161 is about 405.2884415786.

The spelling of 66572161 in words is "sixty-six million, five hundred seventy-two thousand, one hundred sixty-one".