51668391 has 16 divisors (see below), whose sum is σ = 74480000. Its totient is φ = 31749408.

The previous prime is 51668377. The next prime is 51668399. The reversal of 51668391 is 19386615.

51668391 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 51668391 - 2⁷ = 51668263 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51668399) 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 15 ways as a sum of consecutive naturals, for example, 10141 + ... + 14358.

It is an arithmetic number, because the mean of its divisors is an integer number (4655000).

Almost surely, 2^51668391 is an apocalyptic number.

51668391 is a deficient number, since it is larger than the sum of its proper divisors (22811609).

51668391 is a wasteful number, since it uses less digits than its factorization.

51668391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24558.

The product of its digits is 38880, while the sum is 39.

The square root of 51668391 is about 7188.0728293472. The cubic root of 51668391 is about 372.4560036922.

The spelling of 51668391 in words is "fifty-one million, six hundred sixty-eight thousand, three hundred ninety-one".