252816021 has 6 divisors (see below), whose sum is σ = 365178710. Its totient is φ = 168544008.

The previous prime is 252816007. The next prime is 252816041. The reversal of 252816021 is 120618252.

It is a happy number.

252816021 is a `hidden beast` number, since 2 + 52 + 8 + 1 + 602 + 1 = 666.

252816021 is digitally balanced in base 2, 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 only one way, i.e., 247590225 + 5225796 = 15735^2 + 2286^2 .

It is not a de Polignac number, because 252816021 - 2¹⁰ = 252814997 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 (252816041) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 14045326 + ... + 14045343.

Almost surely, 2^252816021 is an apocalyptic number.

It is an amenable number.

252816021 is a deficient number, since it is larger than the sum of its proper divisors (112362689).

252816021 is a wasteful number, since it uses less digits than its factorization.

252816021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28090675 (or 28090672 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 27.

The square root of 252816021 is about 15900.1893384953. The cubic root of 252816021 is about 632.3170085179.

It can be divided in two parts, 2528160 and 21, that multiplied together give a triangular number (53091360 = T₁₀₃₀₄).

The spelling of 252816021 in words is "two hundred fifty-two million, eight hundred sixteen thousand, twenty-one".