51347581997 has 4 divisors (see below), whose sum is σ = 51348042816. Its totient is φ = 51347121180.

The previous prime is 51347581993. The next prime is 51347582029. The reversal of 51347581997 is 79918574315.

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, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 79918574315 = 5 ⋅15983714863.

It is a cyclic number.

It is not a de Polignac number, because 51347581997 - 2² = 51347581993 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 (51347581991) 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, 52622 + ... + 324752.

It is an arithmetic number, because the mean of its divisors is an integer number (12837010704).

Almost surely, 2^51347581997 is an apocalyptic number.

It is an amenable number.

51347581997 is a deficient number, since it is larger than the sum of its proper divisors (460819).

51347581997 is a wasteful number, since it uses less digits than its factorization.

51347581997 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 460818.

The product of its digits is 9525600, while the sum is 59.

The spelling of 51347581997 in words is "fifty-one billion, three hundred forty-seven million, five hundred eighty-one thousand, nine hundred ninety-seven".