51821321 has 8 divisors (see below), whose sum is σ = 56146464. Its totient is φ = 47638080.

The previous prime is 51821309. The next prime is 51821339. The reversal of 51821321 is 12312815.

It is a happy number.

51821321 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 51821321 - 2¹⁰ = 51820297 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51821381) 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 7 ways as a sum of consecutive naturals, for example, 34715 + ... + 36176.

It is an arithmetic number, because the mean of its divisors is an integer number (7018308).

Almost surely, 2^51821321 is an apocalyptic number.

It is an amenable number.

51821321 is a deficient number, since it is larger than the sum of its proper divisors (4325143).

51821321 is a wasteful number, since it uses less digits than its factorization.

51821321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 70951.

The product of its digits is 480, while the sum is 23.

The square root of 51821321 is about 7198.7027303536. The cubic root of 51821321 is about 372.8231113870.

The spelling of 51821321 in words is "fifty-one million, eight hundred twenty-one thousand, three hundred twenty-one".