51256805 has 4 divisors (see below), whose sum is σ = 61508172. Its totient is φ = 41005440.

The previous prime is 51256789. The next prime is 51256823. The reversal of 51256805 is 50865215.

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

It can be written as a sum of positive squares in 2 ways, for example, as 30481441 + 20775364 = 5521^2 + 4558^2 .

It is not a de Polignac number, because 51256805 - 2⁴ = 51256789 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5125676 + ... + 5125685.

It is an arithmetic number, because the mean of its divisors is an integer number (15377043).

Almost surely, 2^51256805 is an apocalyptic number.

It is an amenable number.

51256805 is a deficient number, since it is larger than the sum of its proper divisors (10251367).

51256805 is a wasteful number, since it uses less digits than its factorization.

51256805 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10251366.

The product of its (nonzero) digits is 12000, while the sum is 32.

The square root of 51256805 is about 7159.3857976785. The cubic root of 51256805 is about 371.4643816910.

The spelling of 51256805 in words is "fifty-one million, two hundred fifty-six thousand, eight hundred five".