21423004331 has 4 divisors (see below), whose sum is σ = 21429876000. Its totient is φ = 21416132664.

The previous prime is 21423004319. The next prime is 21423004411. The reversal of 21423004331 is 13340032412.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21423004331 is a prime.

It is a super-2 number, since 2×21423004331² (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 = 21423004297 and 21423004306.

It is not an unprimeable number, because it can be changed into a prime (21423004301) 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, 3431156 + ... + 3437393.

It is an arithmetic number, because the mean of its divisors is an integer number (5357469000).

Almost surely, 2^21423004331 is an apocalyptic number.

21423004331 is a deficient number, since it is larger than the sum of its proper divisors (6871669).

21423004331 is an equidigital number, since it uses as much as digits as its factorization.

21423004331 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6871668.

The product of its (nonzero) digits is 1728, while the sum is 23.

Adding to 21423004331 its reverse (13340032412), we get a palindrome (34763036743).

The spelling of 21423004331 in words is "twenty-one billion, four hundred twenty-three million, four thousand, three hundred thirty-one".