66021161 has 4 divisors (see below), whose sum is σ = 66109824. Its totient is φ = 65932500.

The previous prime is 66021133. The next prime is 66021173. The reversal of 66021161 is 16112066.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 16112066 = 2 ⋅8056033.

It is a cyclic number.

It is not a de Polignac number, because 66021161 - 2⁶ = 66021097 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66021961) 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, 43205 + ... + 44706.

It is an arithmetic number, because the mean of its divisors is an integer number (16527456).

Almost surely, 2^66021161 is an apocalyptic number.

It is an amenable number.

66021161 is a deficient number, since it is larger than the sum of its proper divisors (88663).

66021161 is an equidigital number, since it uses as much as digits as its factorization.

66021161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 88662.

The product of its (nonzero) digits is 432, while the sum is 23.

The square root of 66021161 is about 8125.3406697812. The cubic root of 66021161 is about 404.1671876896.

The spelling of 66021161 in words is "sixty-six million, twenty-one thousand, one hundred sixty-one".