66221306 has 4 divisors (see below), whose sum is σ = 99331962. Its totient is φ = 33110652.

The previous prime is 66221291. The next prime is 66221317. The reversal of 66221306 is 60312266.

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

It can be written as a sum of positive squares in only one way, i.e., 48874081 + 17347225 = 6991^2 + 4165^2 .

It is a super-2 number, since 2×66221306² = 8770522736691272, which contains 22 as substring.

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 as a sum of consecutive naturals, namely, 16555325 + ... + 16555328.

Almost surely, 2^66221306 is an apocalyptic number.

66221306 is a deficient number, since it is larger than the sum of its proper divisors (33110656).

66221306 is a wasteful number, since it uses less digits than its factorization.

66221306 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33110655.

The product of its (nonzero) digits is 2592, while the sum is 26.

The square root of 66221306 is about 8137.6474487409. The cubic root of 66221306 is about 404.5751903955.

The spelling of 66221306 in words is "sixty-six million, two hundred twenty-one thousand, three hundred six".