65321621 has 2 divisors, whose sum is σ = 65321622. Its totient is φ = 65321620.

The previous prime is 65321617. The next prime is 65321623. The reversal of 65321621 is 12612356.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 62884900 + 2436721 = 7930^2 + 1561^2 .

It is a cyclic number.

It is not a de Polignac number, because 65321621 - 2² = 65321617 is a prime.

Together with 65321623, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (65321623) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32660810 + 32660811.

It is an arithmetic number, because the mean of its divisors is an integer number (32660811).

Almost surely, 2^65321621 is an apocalyptic number.

It is an amenable number.

65321621 is a deficient number, since it is larger than the sum of its proper divisors (1).

65321621 is an equidigital number, since it uses as much as digits as its factorization.

65321621 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2160, while the sum is 26.

The square root of 65321621 is about 8082.1792234521. The cubic root of 65321621 is about 402.7346388544.

Adding to 65321621 its reverse (12612356), we get a palindrome (77933977).

The spelling of 65321621 in words is "sixty-five million, three hundred twenty-one thousand, six hundred twenty-one".