252215021 has 4 divisors (see below), whose sum is σ = 252322812. Its totient is φ = 252107232.

The previous prime is 252215011. The next prime is 252215057. The reversal of 252215021 is 120512252.

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 25110121 + 227104900 = 5011^2 + 15070^2 .

It is a cyclic number.

It is not a de Polignac number, because 252215021 - 2⁶ = 252214957 is a prime.

It is a super-2 number, since 2×252215021² = 127224833636060882, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 252214984 and 252215002.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (252215011) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 50306 + ... + 55091.

It is an arithmetic number, because the mean of its divisors is an integer number (63080703).

Almost surely, 2^252215021 is an apocalyptic number.

It is an amenable number.

252215021 is a deficient number, since it is larger than the sum of its proper divisors (107791).

252215021 is a wasteful number, since it uses less digits than its factorization.

252215021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 107790.

The product of its (nonzero) digits is 400, while the sum is 20.

The square root of 252215021 is about 15881.2789472385. The cubic root of 252215021 is about 631.8155581593.

Adding to 252215021 its reverse (120512252), we get a palindrome (372727273).

The spelling of 252215021 in words is "two hundred fifty-two million, two hundred fifteen thousand, twenty-one".