21312033231 has 4 divisors (see below), whose sum is σ = 28416044312. Its totient is φ = 14208022152.

The previous prime is 21312033209. The next prime is 21312033241. The reversal of 21312033231 is 13233021312.

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

It is not a de Polignac number, because 21312033231 - 2¹⁸ = 21311771087 is a prime.

It is a super-2 number, since 2×21312033231² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21312033198 and 21312033207.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21312033241) 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, 3552005536 + ... + 3552005541.

It is an arithmetic number, because the mean of its divisors is an integer number (7104011078).

Almost surely, 2^21312033231 is an apocalyptic number.

21312033231 is a deficient number, since it is larger than the sum of its proper divisors (7104011081).

21312033231 is an equidigital number, since it uses as much as digits as its factorization.

21312033231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7104011080.

The product of its (nonzero) digits is 648, while the sum is 21.

Adding to 21312033231 its reverse (13233021312), we get a palindrome (34545054543).

The spelling of 21312033231 in words is "twenty-one billion, three hundred twelve million, thirty-three thousand, two hundred thirty-one".