51551440421 has 12 divisors (see below), whose sum is σ = 57622688640. Its totient is φ = 46050909840.

The previous prime is 51551440397. The next prime is 51551440427. The reversal of 51551440421 is 12404415515.

It is a happy number.

It is not a de Polignac number, because 51551440421 - 2¹⁰ = 51551439397 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51551440427) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4914731 + ... + 4925208.

It is an arithmetic number, because the mean of its divisors is an integer number (4801890720).

Almost surely, 2^51551440421 is an apocalyptic number.

It is an amenable number.

51551440421 is a deficient number, since it is larger than the sum of its proper divisors (6071248219).

51551440421 is a wasteful number, since it uses less digits than its factorization.

51551440421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9839996 (or 9839983 counting only the distinct ones).

The product of its (nonzero) digits is 16000, while the sum is 32.

Adding to 51551440421 its reverse (12404415515), we get a palindrome (63955855936).

The spelling of 51551440421 in words is "fifty-one billion, five hundred fifty-one million, four hundred forty thousand, four hundred twenty-one".