51519991 has 2 divisors, whose sum is σ = 51519992. Its totient is φ = 51519990.

The previous prime is 51519983. The next prime is 51520003. The reversal of 51519991 is 19991515.

51519991 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 51519991 - 2³ = 51519983 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51519491) 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, 25759995 + 25759996.

It is an arithmetic number, because the mean of its divisors is an integer number (25759996).

Almost surely, 2^51519991 is an apocalyptic number.

51519991 is a deficient number, since it is larger than the sum of its proper divisors (1).

51519991 is an equidigital number, since it uses as much as digits as its factorization.

51519991 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 18225, while the sum is 40.

The square root of 51519991 is about 7177.7427510325. The cubic root of 51519991 is about 372.0990770707.

The spelling of 51519991 in words is "fifty-one million, five hundred nineteen thousand, nine hundred ninety-one".