51042421 has 4 divisors (see below), whose sum is σ = 51879244. Its totient is φ = 50205600.

The previous prime is 51042373. The next prime is 51042457. The reversal of 51042421 is 12424015.

51042421 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12424015 = 5 ⋅2484803.

It can be written as a sum of positive squares in 2 ways, for example, as 3845521 + 47196900 = 1961^2 + 6870^2 .

It is a cyclic number.

It is not a de Polignac number, because 51042421 - 2⁷ = 51042293 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51042491) 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 3 ways as a sum of consecutive naturals, for example, 418320 + ... + 418441.

It is an arithmetic number, because the mean of its divisors is an integer number (12969811).

Almost surely, 2^51042421 is an apocalyptic number.

It is an amenable number.

51042421 is a deficient number, since it is larger than the sum of its proper divisors (836823).

51042421 is an equidigital number, since it uses as much as digits as its factorization.

51042421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 836822.

The product of its (nonzero) digits is 320, while the sum is 19.

The square root of 51042421 is about 7144.3978752586. The cubic root of 51042421 is about 370.9457688887.

Adding to 51042421 its reverse (12424015), we get a palindrome (63466436).

The spelling of 51042421 in words is "fifty-one million, forty-two thousand, four hundred twenty-one".