51656134121 has 4 divisors (see below), whose sum is σ = 53052245892. Its totient is φ = 50260022352.

The previous prime is 51656134109. The next prime is 51656134129. The reversal of 51656134121 is 12143165615.

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 38078058496 + 13578075625 = 195136^2 + 116525^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-51656134121 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51656134129) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 698055830 + ... + 698055903.

It is an arithmetic number, because the mean of its divisors is an integer number (13263061473).

Almost surely, 2^51656134121 is an apocalyptic number.

It is an amenable number.

51656134121 is a deficient number, since it is larger than the sum of its proper divisors (1396111771).

51656134121 is a wasteful number, since it uses less digits than its factorization.

51656134121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1396111770.

The product of its digits is 21600, while the sum is 35.

Adding to 51656134121 its reverse (12143165615), we get a palindrome (63799299736).

The spelling of 51656134121 in words is "fifty-one billion, six hundred fifty-six million, one hundred thirty-four thousand, one hundred twenty-one".