51681722 has 4 divisors (see below), whose sum is σ = 77522586. Its totient is φ = 25840860.

The previous prime is 51681719. The next prime is 51681739. The reversal of 51681722 is 22718615.

51681722 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Cunningham number, because it is equal to 7189²+1.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 22718615 = 5 ⋅4543723.

It can be written as a sum of positive squares in only one way, i.e., 51681721 + 1 = 7189^2 + 1^2 .

It is an unprimeable number.

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, 12920429 + ... + 12920432.

Almost surely, 2^51681722 is an apocalyptic number.

51681722 is a deficient number, since it is larger than the sum of its proper divisors (25840864).

51681722 is a wasteful number, since it uses less digits than its factorization.

51681722 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25840863.

The product of its digits is 6720, while the sum is 32.

The square root of 51681722 is about 7189.0000695507. Note that the first 4 decimals coincide. The cubic root of 51681722 is about 372.4880334879.

The spelling of 51681722 in words is "fifty-one million, six hundred eighty-one thousand, seven hundred twenty-two".