21200304553 has 2 divisors, whose sum is σ = 21200304554. Its totient is φ = 21200304552.

The previous prime is 21200304493. The next prime is 21200304581. The reversal of 21200304553 is 35540300212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16586091369 + 4614213184 = 128787^2 + 67928^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21200304553 is a prime.

It is not a weakly prime, because it can be changed into another prime (21200304953) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10600152276 + 10600152277.

It is an arithmetic number, because the mean of its divisors is an integer number (10600152277).

Almost surely, 2^21200304553 is an apocalyptic number.

It is an amenable number.

21200304553 is a deficient number, since it is larger than the sum of its proper divisors (1).

21200304553 is an equidigital number, since it uses as much as digits as its factorization.

21200304553 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3600, while the sum is 25.

Adding to 21200304553 its reverse (35540300212), we get a palindrome (56740604765).

The spelling of 21200304553 in words is "twenty-one billion, two hundred million, three hundred four thousand, five hundred fifty-three".