21221311001 has 4 divisors (see below), whose sum is σ = 23150521104. Its totient is φ = 19292100900.

The previous prime is 21221310997. The next prime is 21221311081. The reversal of 21221311001 is 10011312212.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21221311001 - 2² = 21221310997 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21221311081) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 964605035 + ... + 964605056.

It is an arithmetic number, because the mean of its divisors is an integer number (5787630276).

Almost surely, 2^21221311001 is an apocalyptic number.

It is an amenable number.

21221311001 is a deficient number, since it is larger than the sum of its proper divisors (1929210103).

21221311001 is a wasteful number, since it uses less digits than its factorization.

21221311001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1929210102.

The product of its (nonzero) digits is 24, while the sum is 14.

Adding to 21221311001 its reverse (10011312212), we get a palindrome (31232623213).

The spelling of 21221311001 in words is "twenty-one billion, two hundred twenty-one million, three hundred eleven thousand, one".