636436121 has 4 divisors (see below), whose sum is σ = 641294544. Its totient is φ = 631577700.

The previous prime is 636436093. The next prime is 636436181. The reversal of 636436121 is 121634636.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-636436121 is a prime.

It is a super-2 number, since 2×636436121² = 810101872227053282, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (636436181) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2429015 + ... + 2429276.

It is an arithmetic number, because the mean of its divisors is an integer number (160323636).

Almost surely, 2^636436121 is an apocalyptic number.

It is an amenable number.

636436121 is a deficient number, since it is larger than the sum of its proper divisors (4858423).

636436121 is a wasteful number, since it uses less digits than its factorization.

636436121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4858422.

The product of its digits is 15552, while the sum is 32.

The square root of 636436121 is about 25227.6856053028. The cubic root of 636436121 is about 860.1712841636.

The spelling of 636436121 in words is "six hundred thirty-six million, four hundred thirty-six thousand, one hundred twenty-one".