405123112421 has 4 divisors (see below), whose sum is σ = 410672744172. Its totient is φ = 399573480672.

The previous prime is 405123112379. The next prime is 405123112453. The reversal of 405123112421 is 124211321504.

It is a happy number.

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 208470775396 + 196652337025 = 456586^2 + 443455^2 .

It is a cyclic number.

It is not a de Polignac number, because 405123112421 - 2²⁶ = 405056003557 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 (405123112721) 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, 2774815766 + ... + 2774815911.

It is an arithmetic number, because the mean of its divisors is an integer number (102668186043).

Almost surely, 2^405123112421 is an apocalyptic number.

It is an amenable number.

405123112421 is a deficient number, since it is larger than the sum of its proper divisors (5549631751).

405123112421 is an equidigital number, since it uses as much as digits as its factorization.

405123112421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5549631750.

The product of its (nonzero) digits is 1920, while the sum is 26.

Adding to 405123112421 its reverse (124211321504), we get a palindrome (529334433925).

The spelling of 405123112421 in words is "four hundred five billion, one hundred twenty-three million, one hundred twelve thousand, four hundred twenty-one".