20623121 has 2 divisors, whose sum is σ = 20623122. Its totient is φ = 20623120.

The previous prime is 20623117. The next prime is 20623129. The reversal of 20623121 is 12132602.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20430400 + 192721 = 4520^2 + 439^2 .

It is a cyclic number.

It is not a de Polignac number, because 20623121 - 2² = 20623117 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20623121.

It is not a weakly prime, because it can be changed into another prime (20623129) 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, 10311560 + 10311561.

It is an arithmetic number, because the mean of its divisors is an integer number (10311561).

Almost surely, 2^20623121 is an apocalyptic number.

It is an amenable number.

20623121 is a deficient number, since it is larger than the sum of its proper divisors (1).

20623121 is an equidigital number, since it uses as much as digits as its factorization.

20623121 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 144, while the sum is 17.

The square root of 20623121 is about 4541.2686553429. The cubic root of 20623121 is about 274.2319993271.

Adding to 20623121 its reverse (12132602), we get a palindrome (32755723).

The spelling of 20623121 in words is "twenty million, six hundred twenty-three thousand, one hundred twenty-one".