21000002221 has 32 divisors (see below), whose sum is σ = 23679226368. Its totient is φ = 18461451840.

The previous prime is 21000002201. The next prime is 21000002249. The reversal of 21000002221 is 12220000012.

It is not a de Polignac number, because 21000002221 - 2⁵ = 21000002189 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21000002198 and 21000002207.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21000002201) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 14159746 + ... + 14161228.

It is an arithmetic number, because the mean of its divisors is an integer number (739975824).

Almost surely, 2^21000002221 is an apocalyptic number.

It is an amenable number.

21000002221 is a deficient number, since it is larger than the sum of its proper divisors (2679224147).

21000002221 is a wasteful number, since it uses less digits than its factorization.

21000002221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1881.

The product of its (nonzero) digits is 16, while the sum is 10.

Adding to 21000002221 its reverse (12220000012), we get a palindrome (33220002233).

The spelling of 21000002221 in words is "twenty-one billion, two thousand, two hundred twenty-one".