252661405 has 4 divisors (see below), whose sum is σ = 303193692. Its totient is φ = 202129120.

The previous prime is 252661399. The next prime is 252661433. The reversal of 252661405 is 504166252.

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 187197124 + 65464281 = 13682^2 + 8091^2 .

It is not a de Polignac number, because 252661405 - 2³ = 252661397 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

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, 25266136 + ... + 25266145.

It is an arithmetic number, because the mean of its divisors is an integer number (75798423).

Almost surely, 2^252661405 is an apocalyptic number.

It is an amenable number.

252661405 is a deficient number, since it is larger than the sum of its proper divisors (50532287).

252661405 is an equidigital number, since it uses as much as digits as its factorization.

252661405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 50532286.

The product of its (nonzero) digits is 14400, while the sum is 31.

The square root of 252661405 is about 15895.3265144193. The cubic root of 252661405 is about 632.1880791045.

The spelling of 252661405 in words is "two hundred fifty-two million, six hundred sixty-one thousand, four hundred five".