21220153 has 2 divisors, whose sum is σ = 21220154. Its totient is φ = 21220152.

The previous prime is 21220109. The next prime is 21220159. The reversal of 21220153 is 35102212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20903184 + 316969 = 4572^2 + 563^2 .

It is a cyclic number.

It is not a de Polignac number, because 21220153 - 2⁹ = 21219641 is a prime.

It is not a weakly prime, because it can be changed into another prime (21220159) 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, 10610076 + 10610077.

It is an arithmetic number, because the mean of its divisors is an integer number (10610077).

Almost surely, 2^21220153 is an apocalyptic number.

It is an amenable number.

21220153 is a deficient number, since it is larger than the sum of its proper divisors (1).

21220153 is an equidigital number, since it uses as much as digits as its factorization.

21220153 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 120, while the sum is 16.

The square root of 21220153 is about 4606.5337293892. The cubic root of 21220153 is about 276.8531719344.

Adding to 21220153 its reverse (35102212), we get a palindrome (56322365).

The spelling of 21220153 in words is "twenty-one million, two hundred twenty thousand, one hundred fifty-three".