21312321001 has 4 divisors (see below), whose sum is σ = 21314050900. Its totient is φ = 21310591104.

The previous prime is 21312320993. The next prime is 21312321007. The reversal of 21312321001 is 10012321312.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 223472601 + 21088848400 = 14949^2 + 145220^2 .

It is a cyclic number.

It is not a de Polignac number, because 21312321001 - 2³ = 21312320993 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21312321007) 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, 846336 + ... + 871153.

It is an arithmetic number, because the mean of its divisors is an integer number (5328512725).

Almost surely, 2^21312321001 is an apocalyptic number.

It is an amenable number.

21312321001 is a deficient number, since it is larger than the sum of its proper divisors (1729899).

21312321001 is a wasteful number, since it uses less digits than its factorization.

21312321001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1729898.

The product of its (nonzero) digits is 72, while the sum is 16.

Adding to 21312321001 its reverse (10012321312), we get a palindrome (31324642313).

The spelling of 21312321001 in words is "twenty-one billion, three hundred twelve million, three hundred twenty-one thousand, one".