21221002205 has 32 divisors (see below), whose sum is σ = 27882102528. Its totient is φ = 15410304000.

The previous prime is 21221002193. The next prime is 21221002217. The reversal of 21221002205 is 50220012212.

It is an interprime number because it is at equal distance from previous prime (21221002193) and next prime (21221002217).

It is not a de Polignac number, because 21221002205 - 2⁴ = 21221002189 is a prime.

It is a super-2 number, since 2×21221002205² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1844882 + ... + 1856348.

It is an arithmetic number, because the mean of its divisors is an integer number (871315704).

Almost surely, 2^21221002205 is an apocalyptic number.

It is an amenable number.

21221002205 is a deficient number, since it is larger than the sum of its proper divisors (6661100323).

21221002205 is a wasteful number, since it uses less digits than its factorization.

21221002205 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11957.

The product of its (nonzero) digits is 160, while the sum is 17.

Adding to 21221002205 its reverse (50220012212), we get a palindrome (71441014417).

The spelling of 21221002205 in words is "twenty-one billion, two hundred twenty-one million, two thousand, two hundred five".