51991646 has 12 divisors (see below), whose sum is σ = 90720288. Its totient is φ = 22282092.

The previous prime is 51991631. The next prime is 51991651. The reversal of 51991646 is 64619915.

51991646 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Curzon number.

It is a congruent number.

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 in 5 ways as a sum of consecutive naturals, for example, 265166 + ... + 265361.

It is an arithmetic number, because the mean of its divisors is an integer number (7560024).

Almost surely, 2^51991646 is an apocalyptic number.

51991646 is a deficient number, since it is larger than the sum of its proper divisors (38728642).

51991646 is a wasteful number, since it uses less digits than its factorization.

51991646 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 530543 (or 530536 counting only the distinct ones).

The product of its digits is 58320, while the sum is 41.

The square root of 51991646 is about 7210.5232819817. The cubic root of 51991646 is about 373.2311265355.

The spelling of 51991646 in words is "fifty-one million, nine hundred ninety-one thousand, six hundred forty-six".