66222561 has 16 divisors (see below), whose sum is σ = 89294400. Its totient is φ = 43653120.

The previous prime is 66222557. The next prime is 66222571. The reversal of 66222561 is 16522266.

It is not a de Polignac number, because 66222561 - 2² = 66222557 is a prime.

It is not an unprimeable number, because it can be changed into a prime (66222571) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 147265 + ... + 147713.

It is an arithmetic number, because the mean of its divisors is an integer number (5580900).

Almost surely, 2^66222561 is an apocalyptic number.

It is an amenable number.

66222561 is a deficient number, since it is larger than the sum of its proper divisors (23071839).

66222561 is a wasteful number, since it uses less digits than its factorization.

66222561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 896.

The product of its digits is 8640, while the sum is 30.

The square root of 66222561 is about 8137.7245591136. The cubic root of 66222561 is about 404.5777461624.

The spelling of 66222561 in words is "sixty-six million, two hundred twenty-two thousand, five hundred sixty-one".