51445781 has 2 divisors, whose sum is σ = 51445782. Its totient is φ = 51445780.

The previous prime is 51445769. The next prime is 51445789. The reversal of 51445781 is 18754415.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 31820881 + 19624900 = 5641^2 + 4430^2 .

It is a cyclic number.

It is not a de Polignac number, because 51445781 - 2⁶ = 51445717 is a prime.

It is a super-2 number, since 2×51445781² = 5293336765399922, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51445789) 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, 25722890 + 25722891.

It is an arithmetic number, because the mean of its divisors is an integer number (25722891).

Almost surely, 2^51445781 is an apocalyptic number.

It is an amenable number.

51445781 is a deficient number, since it is larger than the sum of its proper divisors (1).

51445781 is an equidigital number, since it uses as much as digits as its factorization.

51445781 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 22400, while the sum is 35.

The square root of 51445781 is about 7172.5714356847. The cubic root of 51445781 is about 371.9203325947.

The spelling of 51445781 in words is "fifty-one million, four hundred forty-five thousand, seven hundred eighty-one".