253217221 has 4 divisors (see below), whose sum is σ = 253523500. Its totient is φ = 252910944.

The previous prime is 253217197. The next prime is 253217243. The reversal of 253217221 is 122712352.

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 131997121 + 121220100 = 11489^2 + 11010^2 .

It is a cyclic number.

It is not a de Polignac number, because 253217221 - 2¹⁷ = 253086149 is a prime.

It is a super-2 number, since 2×253217221² = 128237922021925682, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (253217521) 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, 151896 + ... + 153553.

It is an arithmetic number, because the mean of its divisors is an integer number (63380875).

Almost surely, 2^253217221 is an apocalyptic number.

It is an amenable number.

253217221 is a deficient number, since it is larger than the sum of its proper divisors (306279).

253217221 is an equidigital number, since it uses as much as digits as its factorization.

253217221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 306278.

The product of its digits is 1680, while the sum is 25.

The square root of 253217221 is about 15912.8005391886. The cubic root of 253217221 is about 632.6513115784.

Adding to 253217221 its reverse (122712352), we get a palindrome (375929573).

The spelling of 253217221 in words is "two hundred fifty-three million, two hundred seventeen thousand, two hundred twenty-one".