51235621 has 2 divisors, whose sum is σ = 51235622. Its totient is φ = 51235620.

The previous prime is 51235619. The next prime is 51235631. The reversal of 51235621 is 12653215.

51235621 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 39062500 + 12173121 = 6250^2 + 3489^2 .

It is a cyclic number.

It is not a de Polignac number, because 51235621 - 2¹ = 51235619 is a prime.

Together with 51235619, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51235601) 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 as a sum of consecutive naturals, namely, 25617810 + 25617811.

It is an arithmetic number, because the mean of its divisors is an integer number (25617811).

Almost surely, 2^51235621 is an apocalyptic number.

It is an amenable number.

51235621 is a deficient number, since it is larger than the sum of its proper divisors (1).

51235621 is an equidigital number, since it uses as much as digits as its factorization.

51235621 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1800, while the sum is 25.

The square root of 51235621 is about 7157.9061882648. The cubic root of 51235621 is about 371.4132002867.

Adding to 51235621 its reverse (12653215), we get a palindrome (63888836).

The spelling of 51235621 in words is "fifty-one million, two hundred thirty-five thousand, six hundred twenty-one".