51381984697 has 4 divisors (see below), whose sum is σ = 51468632820. Its totient is φ = 51295336576.

The previous prime is 51381984653. The next prime is 51381984707. The reversal of 51381984697 is 79648918315.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 27930431376 + 23451553321 = 167124^2 + 153139^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-51381984697 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51381984607) 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, 43323172 + ... + 43324357.

It is an arithmetic number, because the mean of its divisors is an integer number (12867158205).

Almost surely, 2^51381984697 is an apocalyptic number.

It is an amenable number.

51381984697 is a deficient number, since it is larger than the sum of its proper divisors (86648123).

51381984697 is an equidigital number, since it uses as much as digits as its factorization.

51381984697 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 86648122.

The product of its digits is 13063680, while the sum is 61.

The spelling of 51381984697 in words is "fifty-one billion, three hundred eighty-one million, nine hundred eighty-four thousand, six hundred ninety-seven".