51808791 has 4 divisors (see below), whose sum is σ = 69078392. Its totient is φ = 34539192.

The previous prime is 51808739. The next prime is 51808817. The reversal of 51808791 is 19780815.

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

It is not a de Polignac number, because 51808791 - 2¹¹ = 51806743 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 (51808091) 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, 8634796 + ... + 8634801.

It is an arithmetic number, because the mean of its divisors is an integer number (17269598).

Almost surely, 2^51808791 is an apocalyptic number.

51808791 is a deficient number, since it is larger than the sum of its proper divisors (17269601).

51808791 is a wasteful number, since it uses less digits than its factorization.

51808791 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17269600.

The product of its (nonzero) digits is 20160, while the sum is 39.

The square root of 51808791 is about 7197.8323820439. The cubic root of 51808791 is about 372.7930603703.

The spelling of 51808791 in words is "fifty-one million, eight hundred eight thousand, seven hundred ninety-one".