1206166221 has 56 divisors (see below), whose sum is σ = 1963858680. Its totient is φ = 736045056.

The previous prime is 1206166177. The next prime is 1206166223. The reversal of 1206166221 is 1226616021.

1206166221 is a `hidden beast` number, since 1 + 20 + 6 + 16 + 622 + 1 = 666.

1206166221 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 8037225 + 1198128996 = 2835^2 + 34614^2 .

It is not a de Polignac number, because 1206166221 - 2²² = 1201971917 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1206166223) by changing a digit.

It is a polite number, since it can be written in 55 ways as a sum of consecutive naturals, for example, 1297885 + ... + 1298813.

It is an arithmetic number, because the mean of its divisors is an integer number (35068905).

Almost surely, 2^1206166221 is an apocalyptic number.

It is an amenable number.

1206166221 is a deficient number, since it is larger than the sum of its proper divisors (757692459).

1206166221 is an equidigital number, since it uses as much as digits as its factorization.

1206166221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1097 (or 1082 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 27.

The square root of 1206166221 is about 34729.9038438058. The cubic root of 1206166221 is about 1064.4756236235.

The spelling of 1206166221 in words is "one billion, two hundred six million, one hundred sixty-six thousand, two hundred twenty-one".