21210223555 has 4 divisors (see below), whose sum is σ = 25452268272. Its totient is φ = 16968178840.

The previous prime is 21210223549. The next prime is 21210223561. The reversal of 21210223555 is 55532201212.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (21210223549) and next prime (21210223561).

It is not a de Polignac number, because 21210223555 - 2¹¹ = 21210221507 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2121022351 + ... + 2121022360.

It is an arithmetic number, because the mean of its divisors is an integer number (6363067068).

Almost surely, 2^21210223555 is an apocalyptic number.

21210223555 is a deficient number, since it is larger than the sum of its proper divisors (4242044717).

21210223555 is an equidigital number, since it uses as much as digits as its factorization.

21210223555 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4242044716.

The product of its (nonzero) digits is 6000, while the sum is 28.

Adding to 21210223555 its reverse (55532201212), we get a palindrome (76742424767).

The spelling of 21210223555 in words is "twenty-one billion, two hundred ten million, two hundred twenty-three thousand, five hundred fifty-five".