51239887 has 8 divisors (see below), whose sum is σ = 54616032. Its totient is φ = 47904000.

The previous prime is 51239863. The next prime is 51239911. The reversal of 51239887 is 78893215.

It is an interprime number because it is at equal distance from previous prime (51239863) and next prime (51239911).

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 51239887 - 2¹⁵ = 51207119 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51239087) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7414 + ... + 12547.

It is an arithmetic number, because the mean of its divisors is an integer number (6827004).

Almost surely, 2^51239887 is an apocalyptic number.

51239887 is a deficient number, since it is larger than the sum of its proper divisors (3376145).

51239887 is a wasteful number, since it uses less digits than its factorization.

51239887 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20129.

The product of its digits is 120960, while the sum is 43.

The square root of 51239887 is about 7158.2041742325. The cubic root of 51239887 is about 371.4235082502.

The spelling of 51239887 in words is "fifty-one million, two hundred thirty-nine thousand, eight hundred eighty-seven".