51905404821 has 4 divisors (see below), whose sum is σ = 69207206432. Its totient is φ = 34603603212.

The previous prime is 51905404777. The next prime is 51905404843. The reversal of 51905404821 is 12840450915.

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 not a de Polignac number, because 51905404821 - 2¹³ = 51905396629 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 51905404821.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51905404861) 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, 8650900801 + ... + 8650900806.

It is an arithmetic number, because the mean of its divisors is an integer number (17301801608).

Almost surely, 2^51905404821 is an apocalyptic number.

It is an amenable number.

51905404821 is a deficient number, since it is larger than the sum of its proper divisors (17301801611).

51905404821 is a wasteful number, since it uses less digits than its factorization.

51905404821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17301801610.

The product of its (nonzero) digits is 57600, while the sum is 39.

The spelling of 51905404821 in words is "fifty-one billion, nine hundred five million, four hundred four thousand, eight hundred twenty-one".