51121613 has 2 divisors, whose sum is σ = 51121614. Its totient is φ = 51121612.

The previous prime is 51121597. The next prime is 51121649. The reversal of 51121613 is 31612115.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 50951044 + 170569 = 7138^2 + 413^2 .

It is a cyclic number.

It is not a de Polignac number, because 51121613 - 2⁴ = 51121597 is a prime.

It is a super-2 number, since 2×51121613² = 5226838631443538, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51121513) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25560806 + 25560807.

It is an arithmetic number, because the mean of its divisors is an integer number (25560807).

Almost surely, 2^51121613 is an apocalyptic number.

It is an amenable number.

51121613 is a deficient number, since it is larger than the sum of its proper divisors (1).

51121613 is an equidigital number, since it uses as much as digits as its factorization.

51121613 is an evil number, because the sum of its binary digits is even.

The product of its digits is 180, while the sum is 20.

The square root of 51121613 is about 7149.9379717589. The cubic root of 51121613 is about 371.1375097821.

Adding to 51121613 its reverse (31612115), we get a palindrome (82733728).

It can be divided in two parts, 5 and 1121613, that multiplied together give a palindrome (5608065).

The spelling of 51121613 in words is "fifty-one million, one hundred twenty-one thousand, six hundred thirteen".