51404809 has 2 divisors, whose sum is σ = 51404810. Its totient is φ = 51404808.

The previous prime is 51404807. The next prime is 51404819. The reversal of 51404809 is 90840415.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 49070025 + 2334784 = 7005^2 + 1528^2 .

It is a cyclic number.

It is not a de Polignac number, because 51404809 - 2¹ = 51404807 is a prime.

Together with 51404807, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (51404807) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25702404 + 25702405.

It is an arithmetic number, because the mean of its divisors is an integer number (25702405).

Almost surely, 2^51404809 is an apocalyptic number.

It is an amenable number.

51404809 is a deficient number, since it is larger than the sum of its proper divisors (1).

51404809 is an equidigital number, since it uses as much as digits as its factorization.

51404809 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5760, while the sum is 31.

The square root of 51404809 is about 7169.7147084106. The cubic root of 51404809 is about 371.8215725236.

The spelling of 51404809 in words is "fifty-one million, four hundred four thousand, eight hundred nine".