51256421 has 2 divisors, whose sum is σ = 51256422. Its totient is φ = 51256420.

The previous prime is 51256417. The next prime is 51256441. The reversal of 51256421 is 12465215.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 43890625 + 7365796 = 6625^2 + 2714^2 .

It is a cyclic number.

It is not a de Polignac number, because 51256421 - 2² = 51256417 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51256441) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25628210 + 25628211.

It is an arithmetic number, because the mean of its divisors is an integer number (25628211).

Almost surely, 2^51256421 is an apocalyptic number.

It is an amenable number.

51256421 is a deficient number, since it is larger than the sum of its proper divisors (1).

51256421 is an equidigital number, since it uses as much as digits as its factorization.

51256421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2400, while the sum is 26.

The square root of 51256421 is about 7159.3589796853. The cubic root of 51256421 is about 371.4634540570.

The spelling of 51256421 in words is "fifty-one million, two hundred fifty-six thousand, four hundred twenty-one".