164727221 has 4 divisors (see below), whose sum is σ = 170407500. Its totient is φ = 159046944.

The previous prime is 164727203. The next prime is 164727239. The reversal of 164727221 is 122727461.

164727221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 122727461 = 43 ⋅2854127.

It is an interprime number because it is at equal distance from previous prime (164727203) and next prime (164727239).

It can be written as a sum of positive squares in 2 ways, for example, as 66994225 + 97732996 = 8185^2 + 9886^2 .

It is a cyclic number.

It is not a de Polignac number, because 164727221 - 2²⁶ = 97618357 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (164727271) 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, 2840096 + ... + 2840153.

It is an arithmetic number, because the mean of its divisors is an integer number (42601875).

Almost surely, 2^164727221 is an apocalyptic number.

It is an amenable number.

164727221 is a deficient number, since it is larger than the sum of its proper divisors (5680279).

164727221 is an equidigital number, since it uses as much as digits as its factorization.

164727221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5680278.

The product of its digits is 9408, while the sum is 32.

The square root of 164727221 is about 12834.6102784619. The cubic root of 164727221 is about 548.1782380149.

The spelling of 164727221 in words is "one hundred sixty-four million, seven hundred twenty-seven thousand, two hundred twenty-one".