51970821647 has 2 divisors, whose sum is σ = 51970821648. Its totient is φ = 51970821646.

The previous prime is 51970821641. The next prime is 51970821649. The reversal of 51970821647 is 74612807915.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 51970821647 - 2¹⁰ = 51970820623 is a prime.

Together with 51970821649, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 51970821595 and 51970821604.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51970821641) 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, 25985410823 + 25985410824.

It is an arithmetic number, because the mean of its divisors is an integer number (25985410824).

Almost surely, 2^51970821647 is an apocalyptic number.

51970821647 is a deficient number, since it is larger than the sum of its proper divisors (1).

51970821647 is an equidigital number, since it uses as much as digits as its factorization.

51970821647 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 846720, while the sum is 50.

The spelling of 51970821647 in words is "fifty-one billion, nine hundred seventy million, eight hundred twenty-one thousand, six hundred forty-seven".