51686987 has 8 divisors (see below), whose sum is σ = 59702832. Its totient is φ = 44224000.

The previous prime is 51686977. The next prime is 51687023. The reversal of 51686987 is 78968615.

It is a happy number.

51686987 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 51686987 - 2⁶ = 51686923 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51686927) 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 7 ways as a sum of consecutive naturals, for example, 138014 + ... + 138387.

It is an arithmetic number, because the mean of its divisors is an integer number (7462854).

Almost surely, 2^51686987 is an apocalyptic number.

51686987 is a deficient number, since it is larger than the sum of its proper divisors (8015845).

51686987 is a wasteful number, since it uses less digits than its factorization.

51686987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 276429.

The product of its digits is 725760, while the sum is 50.

The square root of 51686987 is about 7189.3662446700. The cubic root of 51686987 is about 372.5006819500.

The spelling of 51686987 in words is "fifty-one million, six hundred eighty-six thousand, nine hundred eighty-seven".