51425844221 has 4 divisors (see below), whose sum is σ = 51427697244. Its totient is φ = 51423991200.

The previous prime is 51425844193. The next prime is 51425844227. The reversal of 51425844221 is 12244852415.

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 47595967225 + 3829876996 = 218165^2 + 61886^2 .

It is a cyclic number.

It is not a de Polignac number, because 51425844221 - 2⁶ = 51425844157 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 (51425844227) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 884240 + ... + 940601.

It is an arithmetic number, because the mean of its divisors is an integer number (12856924311).

Almost surely, 2^51425844221 is an apocalyptic number.

It is an amenable number.

51425844221 is a deficient number, since it is larger than the sum of its proper divisors (1853023).

51425844221 is a wasteful number, since it uses less digits than its factorization.

51425844221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1853022.

The product of its digits is 102400, while the sum is 38.

The spelling of 51425844221 in words is "fifty-one billion, four hundred twenty-five million, eight hundred forty-four thousand, two hundred twenty-one".