21012232221 has 16 divisors (see below), whose sum is σ = 32767614400. Its totient is φ = 13270883184.

The previous prime is 21012232207. The next prime is 21012232223. The reversal of 21012232221 is 12223221012.

21012232221 is a `hidden beast` number, since 210 + 1 + 2 + 232 + 221 = 666.

It is not a de Polignac number, because 21012232221 - 2¹⁹ = 21011707933 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21012232194 and 21012232203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21012232223) 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 15 ways as a sum of consecutive naturals, for example, 20479246 + ... + 20480271.

It is an arithmetic number, because the mean of its divisors is an integer number (2047975900).

Almost surely, 2^21012232221 is an apocalyptic number.

It is an amenable number.

21012232221 is a deficient number, since it is larger than the sum of its proper divisors (11755382179).

21012232221 is a wasteful number, since it uses less digits than its factorization.

21012232221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40959545 (or 40959539 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

Adding to 21012232221 its reverse (12223221012), we get a palindrome (33235453233).

It can be divided in two parts, 2101 and 2232221, that added together give a palindrome (2234322).

The spelling of 21012232221 in words is "twenty-one billion, twelve million, two hundred thirty-two thousand, two hundred twenty-one".