51516121 has 4 divisors (see below), whose sum is σ = 51584932. Its totient is φ = 51447312.

The previous prime is 51516097. The next prime is 51516167. The reversal of 51516121 is 12161515.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 20602521 + 30913600 = 4539^2 + 5560^2 .

It is a cyclic number.

It is not a de Polignac number, because 51516121 - 2⁹ = 51515609 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 51516092 and 51516101.

It is not an unprimeable number, because it can be changed into a prime (51516221) 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, 33270 + ... + 34783.

It is an arithmetic number, because the mean of its divisors is an integer number (12896233).

Almost surely, 2^51516121 is an apocalyptic number.

It is an amenable number.

51516121 is a deficient number, since it is larger than the sum of its proper divisors (68811).

51516121 is an equidigital number, since it uses as much as digits as its factorization.

51516121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 68810.

The product of its digits is 300, while the sum is 22.

The square root of 51516121 is about 7177.4731626109. The cubic root of 51516121 is about 372.0897599141.

Adding to 51516121 its reverse (12161515), we get a palindrome (63677636).

The spelling of 51516121 in words is "fifty-one million, five hundred sixteen thousand, one hundred twenty-one".