51787217 has 4 divisors (see below), whose sum is σ = 54512880. Its totient is φ = 49061556.

The previous prime is 51787193. The next prime is 51787247. The reversal of 51787217 is 71278715.

51787217 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, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 51787217 - 2¹⁸ = 51525073 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51787247) 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, 1362803 + ... + 1362840.

It is an arithmetic number, because the mean of its divisors is an integer number (13628220).

Almost surely, 2^51787217 is an apocalyptic number.

It is an amenable number.

51787217 is a deficient number, since it is larger than the sum of its proper divisors (2725663).

51787217 is a wasteful number, since it uses less digits than its factorization.

51787217 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2725662.

The product of its digits is 27440, while the sum is 38.

The square root of 51787217 is about 7196.3335803727. Note that the first 3 decimals coincide. The cubic root of 51787217 is about 372.7413075439.

The spelling of 51787217 in words is "fifty-one million, seven hundred eighty-seven thousand, two hundred seventeen".