21645005323 has 8 divisors (see below), whose sum is σ = 22259199600. Its totient is φ = 21039055488.

The previous prime is 21645005303. The next prime is 21645005341. The reversal of 21645005323 is 32350054612.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 21645005323 - 2¹³ = 21644997131 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21645005303) 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, 2055786 + ... + 2066287.

It is an arithmetic number, because the mean of its divisors is an integer number (2782399950).

Almost surely, 2^21645005323 is an apocalyptic number.

21645005323 is a deficient number, since it is larger than the sum of its proper divisors (614194277).

21645005323 is an equidigital number, since it uses as much as digits as its factorization.

21645005323 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4122221.

The product of its (nonzero) digits is 21600, while the sum is 31.

Adding to 21645005323 its reverse (32350054612), we get a palindrome (53995059935).

The spelling of 21645005323 in words is "twenty-one billion, six hundred forty-five million, five thousand, three hundred twenty-three".