51809000251 has 2 divisors, whose sum is σ = 51809000252. Its totient is φ = 51809000250.

The previous prime is 51809000237. The next prime is 51809000293. The reversal of 51809000251 is 15200090815.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 51809000251 - 2⁷ = 51809000123 is a prime.

It is not a weakly prime, because it can be changed into another prime (51809000051) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25904500125 + 25904500126.

It is an arithmetic number, because the mean of its divisors is an integer number (25904500126).

Almost surely, 2^51809000251 is an apocalyptic number.

51809000251 is a deficient number, since it is larger than the sum of its proper divisors (1).

51809000251 is an equidigital number, since it uses as much as digits as its factorization.

51809000251 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3600, while the sum is 31.

The spelling of 51809000251 in words is "fifty-one billion, eight hundred nine million, two hundred fifty-one", and thus it is an aban number.