51331603721 has 2 divisors, whose sum is σ = 51331603722. Its totient is φ = 51331603720.

The previous prime is 51331603663. The next prime is 51331603723. The reversal of 51331603721 is 12730613315.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 51218479225 + 113124496 = 226315^2 + 10636^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-51331603721 is a prime.

Together with 51331603723, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (51331603723) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25665801860 + 25665801861.

It is an arithmetic number, because the mean of its divisors is an integer number (25665801861).

Almost surely, 2^51331603721 is an apocalyptic number.

It is an amenable number.

51331603721 is a deficient number, since it is larger than the sum of its proper divisors (1).

51331603721 is an equidigital number, since it uses as much as digits as its factorization.

51331603721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 11340, while the sum is 32.

The spelling of 51331603721 in words is "fifty-one billion, three hundred thirty-one million, six hundred three thousand, seven hundred twenty-one".