252691821 has 6 divisors (see below), whose sum is σ = 364999310. Its totient is φ = 168461208.

The previous prime is 252691801. The next prime is 252691847. The reversal of 252691821 is 128196252.

It can be written as a sum of positive squares in only one way, i.e., 177262596 + 75429225 = 13314^2 + 8685^2 .

It is not a de Polignac number, because 252691821 - 2¹⁵ = 252659053 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 (252691801) 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 5 ways as a sum of consecutive naturals, for example, 14038426 + ... + 14038443.

Almost surely, 2^252691821 is an apocalyptic number.

It is an amenable number.

252691821 is a deficient number, since it is larger than the sum of its proper divisors (112307489).

252691821 is a wasteful number, since it uses less digits than its factorization.

252691821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28076875 (or 28076872 counting only the distinct ones).

The product of its digits is 17280, while the sum is 36.

The square root of 252691821 is about 15896.2832448343. The cubic root of 252691821 is about 632.2134462041.

The spelling of 252691821 in words is "two hundred fifty-two million, six hundred ninety-one thousand, eight hundred twenty-one".