51387509 has 2 divisors, whose sum is σ = 51387510. Its totient is φ = 51387508.

The previous prime is 51387397. The next prime is 51387517. The reversal of 51387509 is 90578315.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 50367409 + 1020100 = 7097^2 + 1010^2 .

It is a cyclic number.

It is not a de Polignac number, because 51387509 - 2¹⁶ = 51321973 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51381509) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25693754 + 25693755.

It is an arithmetic number, because the mean of its divisors is an integer number (25693755).

Almost surely, 2^51387509 is an apocalyptic number.

It is an amenable number.

51387509 is a deficient number, since it is larger than the sum of its proper divisors (1).

51387509 is an equidigital number, since it uses as much as digits as its factorization.

51387509 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 37800, while the sum is 38.

The square root of 51387509 is about 7168.5081432611. The cubic root of 51387509 is about 371.7798563555.

The spelling of 51387509 in words is "fifty-one million, three hundred eighty-seven thousand, five hundred nine".