636120427121 has 4 divisors (see below), whose sum is σ = 636818694144. Its totient is φ = 635422160100.

The previous prime is 636120427109. The next prime is 636120427153. The reversal of 636120427121 is 121724021636.

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-636120427121 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (636120427181) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 349132145 + ... + 349133966.

It is an arithmetic number, because the mean of its divisors is an integer number (159204673536).

Almost surely, 2^636120427121 is an apocalyptic number.

It is an amenable number.

636120427121 is a deficient number, since it is larger than the sum of its proper divisors (698267023).

636120427121 is an equidigital number, since it uses as much as digits as its factorization.

636120427121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 698267022.

The product of its (nonzero) digits is 24192, while the sum is 35.

Adding to 636120427121 its reverse (121724021636), we get a palindrome (757844448757).

The spelling of 636120427121 in words is "six hundred thirty-six billion, one hundred twenty million, four hundred twenty-seven thousand, one hundred twenty-one".