51215887 has 4 divisors (see below), whose sum is σ = 53911480. Its totient is φ = 48520296.

The previous prime is 51215869. The next prime is 51215893. The reversal of 51215887 is 78851215.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-51215887 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 (51215287) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1347768 + ... + 1347805.

It is an arithmetic number, because the mean of its divisors is an integer number (13477870).

Almost surely, 2^51215887 is an apocalyptic number.

51215887 is a deficient number, since it is larger than the sum of its proper divisors (2695593).

51215887 is a wasteful number, since it uses less digits than its factorization.

51215887 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2695592.

The product of its digits is 22400, while the sum is 37.

The square root of 51215887 is about 7156.5275797694. The cubic root of 51215887 is about 371.3655094474.

The spelling of 51215887 in words is "fifty-one million, two hundred fifteen thousand, eight hundred eighty-seven".