51256156421 has 2 divisors, whose sum is σ = 51256156422. Its totient is φ = 51256156420.

The previous prime is 51256156387. The next prime is 51256156429. The reversal of 51256156421 is 12465165215.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 49155767521 + 2100388900 = 221711^2 + 45830^2 .

It is a cyclic number.

It is not a de Polignac number, because 51256156421 - 2¹⁰ = 51256155397 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51256156429) 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, 25628078210 + 25628078211.

It is an arithmetic number, because the mean of its divisors is an integer number (25628078211).

Almost surely, 2^51256156421 is an apocalyptic number.

It is an amenable number.

51256156421 is a deficient number, since it is larger than the sum of its proper divisors (1).

51256156421 is an equidigital number, since it uses as much as digits as its factorization.

51256156421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 72000, while the sum is 38.

The spelling of 51256156421 in words is "fifty-one billion, two hundred fifty-six million, one hundred fifty-six thousand, four hundred twenty-one".