1066645221 has 4 divisors (see below), whose sum is σ = 1422193632. Its totient is φ = 711096812.

The previous prime is 1066645169. The next prime is 1066645249. The reversal of 1066645221 is 1225466601.

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.

It is a cyclic number.

It is not a de Polignac number, because 1066645221 - 2⁶ = 1066645157 is a prime.

It is a super-3 number, since 3×1066645221³ (a number of 28 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1066645291) 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, 177774201 + ... + 177774206.

It is an arithmetic number, because the mean of its divisors is an integer number (355548408).

Almost surely, 2^1066645221 is an apocalyptic number.

It is an amenable number.

1066645221 is a deficient number, since it is larger than the sum of its proper divisors (355548411).

1066645221 is an equidigital number, since it uses as much as digits as its factorization.

1066645221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 355548410.

The product of its (nonzero) digits is 17280, while the sum is 33.

The square root of 1066645221 is about 32659.5349170805. The cubic root of 1066645221 is about 1021.7390623052.

The spelling of 1066645221 in words is "one billion, sixty-six million, six hundred forty-five thousand, two hundred twenty-one".