20045621 has 2 divisors, whose sum is σ = 20045622. Its totient is φ = 20045620.

The previous prime is 20045617. The next prime is 20045629. The reversal of 20045621 is 12654002.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14546596 + 5499025 = 3814^2 + 2345^2 .

It is a cyclic number.

It is not a de Polignac number, because 20045621 - 2² = 20045617 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20045593 and 20045602.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20045629) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10022810 + 10022811.

It is an arithmetic number, because the mean of its divisors is an integer number (10022811).

Almost surely, 2^20045621 is an apocalyptic number.

It is an amenable number.

20045621 is a deficient number, since it is larger than the sum of its proper divisors (1).

20045621 is an equidigital number, since it uses as much as digits as its factorization.

20045621 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 480, while the sum is 20.

The square root of 20045621 is about 4477.2336325012. The cubic root of 20045621 is about 271.6479956723.

Adding to 20045621 its reverse (12654002), we get a palindrome (32699623).

The spelling of 20045621 in words is "twenty million, forty-five thousand, six hundred twenty-one".