51491507 has 2 divisors, whose sum is σ = 51491508. Its totient is φ = 51491506.

The previous prime is 51491497. The next prime is 51491509. The reversal of 51491507 is 70519415.

51491507 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 51491507 - 2¹⁸ = 51229363 is a prime.

Together with 51491509, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (51491509) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25745753 + 25745754.

It is an arithmetic number, because the mean of its divisors is an integer number (25745754).

Almost surely, 2^51491507 is an apocalyptic number.

51491507 is a deficient number, since it is larger than the sum of its proper divisors (1).

51491507 is an equidigital number, since it uses as much as digits as its factorization.

51491507 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6300, while the sum is 32.

The square root of 51491507 is about 7175.7582874565. The cubic root of 51491507 is about 372.0304899470.

The spelling of 51491507 in words is "fifty-one million, four hundred ninety-one thousand, five hundred seven".