51728131421 has 4 divisors (see below), whose sum is σ = 52500193152. Its totient is φ = 50956069692.

The previous prime is 51728131397. The next prime is 51728131453. The reversal of 51728131421 is 12413182715.

51728131421 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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-51728131421 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 (51728131321) 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, 386030765 + ... + 386030898.

It is an arithmetic number, because the mean of its divisors is an integer number (13125048288).

Almost surely, 2^51728131421 is an apocalyptic number.

It is an amenable number.

51728131421 is a deficient number, since it is larger than the sum of its proper divisors (772061731).

51728131421 is an equidigital number, since it uses as much as digits as its factorization.

51728131421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 772061730.

The product of its digits is 13440, while the sum is 35.

The spelling of 51728131421 in words is "fifty-one billion, seven hundred twenty-eight million, one hundred thirty-one thousand, four hundred twenty-one".