51643409 has 2 divisors, whose sum is σ = 51643410. Its totient is φ = 51643408.

The previous prime is 51643391. The next prime is 51643429. The reversal of 51643409 is 90434615.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 30913600 + 20729809 = 5560^2 + 4553^2 .

It is a cyclic number.

It is not a de Polignac number, because 51643409 - 2²⁰ = 50594833 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (51643429) 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, 25821704 + 25821705.

It is an arithmetic number, because the mean of its divisors is an integer number (25821705).

Almost surely, 2^51643409 is an apocalyptic number.

It is an amenable number.

51643409 is a deficient number, since it is larger than the sum of its proper divisors (1).

51643409 is an equidigital number, since it uses as much as digits as its factorization.

51643409 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 12960, while the sum is 32.

The square root of 51643409 is about 7186.3348794779. The cubic root of 51643409 is about 372.3959657223.

The spelling of 51643409 in words is "fifty-one million, six hundred forty-three thousand, four hundred nine".