51612321 has 4 divisors (see below), whose sum is σ = 68816432. Its totient is φ = 34408212.

The previous prime is 51612307. The next prime is 51612329. The reversal of 51612321 is 12321615.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 51612321 - 2⁷ = 51612193 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51612329) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8602051 + ... + 8602056.

It is an arithmetic number, because the mean of its divisors is an integer number (17204108).

Almost surely, 2^51612321 is an apocalyptic number.

It is an amenable number.

51612321 is a deficient number, since it is larger than the sum of its proper divisors (17204111).

51612321 is a wasteful number, since it uses less digits than its factorization.

51612321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17204110.

The product of its digits is 360, while the sum is 21.

The square root of 51612321 is about 7184.1715597555. The cubic root of 51612321 is about 372.3212264683.

Adding to 51612321 its reverse (12321615), we get a palindrome (63933936).

The spelling of 51612321 in words is "fifty-one million, six hundred twelve thousand, three hundred twenty-one".