51121021 has 4 divisors (see below), whose sum is σ = 58424032. Its totient is φ = 43818012.

The previous prime is 51121009. The next prime is 51121033. The reversal of 51121021 is 12012115.

51121021 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 a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (51121009) and next prime (51121033).

It is not a de Polignac number, because 51121021 - 2⁷ = 51120893 is a prime.

It is a super-2 number, since 2×51121021² = 5226717576164882, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 51120992 and 51121010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51121061) 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, 3651495 + ... + 3651508.

It is an arithmetic number, because the mean of its divisors is an integer number (14606008).

Almost surely, 2^51121021 is an apocalyptic number.

It is an amenable number.

51121021 is a deficient number, since it is larger than the sum of its proper divisors (7303011).

51121021 is an equidigital number, since it uses as much as digits as its factorization.

51121021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7303010.

The product of its (nonzero) digits is 20, while the sum is 13.

The square root of 51121021 is about 7149.8965726785. The cubic root of 51121021 is about 371.1360771574.

Adding to 51121021 its reverse (12012115), we get a palindrome (63133136).

The spelling of 51121021 in words is "fifty-one million, one hundred twenty-one thousand, twenty-one".