51056809 has 2 divisors, whose sum is σ = 51056810. Its totient is φ = 51056808.

The previous prime is 51056807. The next prime is 51056827. The reversal of 51056809 is 90865015.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 29942784 + 21114025 = 5472^2 + 4595^2 .

It is a cyclic number.

It is not a de Polignac number, because 51056809 - 2¹ = 51056807 is a prime.

Together with 51056807, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (51056807) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25528404 + 25528405.

It is an arithmetic number, because the mean of its divisors is an integer number (25528405).

Almost surely, 2^51056809 is an apocalyptic number.

It is an amenable number.

51056809 is a deficient number, since it is larger than the sum of its proper divisors (1).

51056809 is an equidigital number, since it uses as much as digits as its factorization.

51056809 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 10800, while the sum is 34.

The square root of 51056809 is about 7145.4047471085. The cubic root of 51056809 is about 370.9806200720.

The spelling of 51056809 in words is "fifty-one million, fifty-six thousand, eight hundred nine".