51581806 has 4 divisors (see below), whose sum is σ = 77372712. Its totient is φ = 25790902.

The previous prime is 51581767. The next prime is 51581809. The reversal of 51581806 is 60818515.

51581806 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.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51581809) 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 as a sum of consecutive naturals, namely, 12895450 + ... + 12895453.

It is an arithmetic number, because the mean of its divisors is an integer number (19343178).

Almost surely, 2^51581806 is an apocalyptic number.

51581806 is a deficient number, since it is larger than the sum of its proper divisors (25790906).

51581806 is a wasteful number, since it uses less digits than its factorization.

51581806 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25790905.

The product of its (nonzero) digits is 9600, while the sum is 34.

The square root of 51581806 is about 7182.0474796537. The cubic root of 51581806 is about 372.2478355814.

The spelling of 51581806 in words is "fifty-one million, five hundred eighty-one thousand, eight hundred six".