21115003221 has 48 divisors (see below), whose sum is σ = 36608120640. Its totient is φ = 11585825280.

The previous prime is 21115003213. The next prime is 21115003229. The reversal of 21115003221 is 12230051112.

21115003221 is a `hidden beast` number, since 2 + 111 + 500 + 32 + 21 = 666.

It is an interprime number because it is at equal distance from previous prime (21115003213) and next prime (21115003229).

It is not a de Polignac number, because 21115003221 - 2³ = 21115003213 is a prime.

It is a super-2 number, since 2×21115003221² (a number of 21 digits) contains 22 as substring.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21115003194 and 21115003203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21115003229) by changing a digit.

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 47 ways as a sum of consecutive naturals, for example, 241575 + ... + 317156.

It is an arithmetic number, because the mean of its divisors is an integer number (762669180).

Almost surely, 2^21115003221 is an apocalyptic number.

It is an amenable number.

21115003221 is a deficient number, since it is larger than the sum of its proper divisors (15493117419).

21115003221 is a wasteful number, since it uses less digits than its factorization.

21115003221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 558786 (or 558783 counting only the distinct ones).

The product of its (nonzero) digits is 120, while the sum is 18.

Adding to 21115003221 its reverse (12230051112), we get a palindrome (33345054333).

The spelling of 21115003221 in words is "twenty-one billion, one hundred fifteen million, three thousand, two hundred twenty-one".