1066221655 has 4 divisors (see below), whose sum is σ = 1279465992. Its totient is φ = 852977320.

The previous prime is 1066221647. The next prime is 1066221659. The reversal of 1066221655 is 5561226601.

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

It is not a de Polignac number, because 1066221655 - 2³ = 1066221647 is a prime.

It is a super-3 number, since 3×1066221655³ (a number of 28 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1066221655.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1066221659) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 106622161 + ... + 106622170.

It is an arithmetic number, because the mean of its divisors is an integer number (319866498).

Almost surely, 2^1066221655 is an apocalyptic number.

1066221655 is a deficient number, since it is larger than the sum of its proper divisors (213244337).

1066221655 is an equidigital number, since it uses as much as digits as its factorization.

1066221655 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 213244336.

The product of its (nonzero) digits is 21600, while the sum is 34.

The square root of 1066221655 is about 32653.0497044304. The cubic root of 1066221655 is about 1021.6037998278.

The spelling of 1066221655 in words is "one billion, sixty-six million, two hundred twenty-one thousand, six hundred fifty-five".