21323204431 has 4 divisors (see below), whose sum is σ = 22577510592. Its totient is φ = 20068898272.

The previous prime is 21323204407. The next prime is 21323204459. The reversal of 21323204431 is 13440232312.

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

It is a cyclic number.

It is not a de Polignac number, because 21323204431 - 2¹⁵ = 21323171663 is a prime.

It is a super-2 number, since 2×21323204431² (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 = 21323204396 and 21323204405.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21323204491) 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, 627153055 + ... + 627153088.

It is an arithmetic number, because the mean of its divisors is an integer number (5644377648).

Almost surely, 2^21323204431 is an apocalyptic number.

21323204431 is a deficient number, since it is larger than the sum of its proper divisors (1254306161).

21323204431 is a wasteful number, since it uses less digits than its factorization.

21323204431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1254306160.

The product of its (nonzero) digits is 3456, while the sum is 25.

Adding to 21323204431 its reverse (13440232312), we get a palindrome (34763436743).

The spelling of 21323204431 in words is "twenty-one billion, three hundred twenty-three million, two hundred four thousand, four hundred thirty-one".