21312312321 has 8 divisors (see below), whose sum is σ = 28427065984. Its totient is φ = 14202883440.

The previous prime is 21312312313. The next prime is 21312312337. The reversal of 21312312321 is 12321321312.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21312312321 - 2³ = 21312312313 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21312312221) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1321846 + ... + 1337871.

It is an arithmetic number, because the mean of its divisors is an integer number (3553383248).

Almost surely, 2^21312312321 is an apocalyptic number.

It is an amenable number.

21312312321 is a deficient number, since it is larger than the sum of its proper divisors (7114753663).

21312312321 is a wasteful number, since it uses less digits than its factorization.

21312312321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2662391.

The product of its digits is 432, while the sum is 21.

Adding to 21312312321 its reverse (12321321312), we get a palindrome (33633633633).

The spelling of 21312312321 in words is "twenty-one billion, three hundred twelve million, three hundred twelve thousand, three hundred twenty-one".