221670121 has 4 divisors (see below), whose sum is σ = 224706772. Its totient is φ = 218633472.

The previous prime is 221670107. The next prime is 221670143. The reversal of 221670121 is 121076122.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 116402521 + 105267600 = 10789^2 + 10260^2 .

It is a cyclic number.

It is not a de Polignac number, because 221670121 - 2²³ = 213281513 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 221670092 and 221670101.

It is not an unprimeable number, because it can be changed into a prime (221670101) 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, 1518216 + ... + 1518361.

It is an arithmetic number, because the mean of its divisors is an integer number (56176693).

Almost surely, 2^221670121 is an apocalyptic number.

It is an amenable number.

221670121 is a deficient number, since it is larger than the sum of its proper divisors (3036651).

221670121 is an equidigital number, since it uses as much as digits as its factorization.

221670121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3036650.

The product of its (nonzero) digits is 336, while the sum is 22.

The square root of 221670121 is about 14888.5902959280. The cubic root of 221670121 is about 605.2048310377.

The spelling of 221670121 in words is "two hundred twenty-one million, six hundred seventy thousand, one hundred twenty-one".