51787987 has 4 divisors (see below), whose sum is σ = 51879256. Its totient is φ = 51696720.

The previous prime is 51787979. The next prime is 51787991. The reversal of 51787987 is 78978715.

51787987 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 51787987 - 2³ = 51787979 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51787907) 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 in 3 ways as a sum of consecutive naturals, for example, 44778 + ... + 45919.

It is an arithmetic number, because the mean of its divisors is an integer number (12969814).

Almost surely, 2^51787987 is an apocalyptic number.

51787987 is a deficient number, since it is larger than the sum of its proper divisors (91269).

51787987 is an equidigital number, since it uses as much as digits as its factorization.

51787987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 91268.

The product of its digits is 987840, while the sum is 52.

The square root of 51787987 is about 7196.3870796393. The cubic root of 51787987 is about 372.7431549070.

The spelling of 51787987 in words is "fifty-one million, seven hundred eighty-seven thousand, nine hundred eighty-seven".