21531342323 has 4 divisors (see below), whose sum is σ = 21803891040. Its totient is φ = 21258793608.

The previous prime is 21531342281. The next prime is 21531342397. The reversal of 21531342323 is 32324313512.

It is a happy number.

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-21531342323 is a prime.

It is a super-2 number, since 2×21531342323² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21531372323) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 136274240 + ... + 136274397.

It is an arithmetic number, because the mean of its divisors is an integer number (5450972760).

Almost surely, 2^21531342323 is an apocalyptic number.

21531342323 is a deficient number, since it is larger than the sum of its proper divisors (272548717).

21531342323 is an equidigital number, since it uses as much as digits as its factorization.

21531342323 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 272548716.

The product of its digits is 12960, while the sum is 29.

Adding to 21531342323 its reverse (32324313512), we get a palindrome (53855655835).

The spelling of 21531342323 in words is "twenty-one billion, five hundred thirty-one million, three hundred forty-two thousand, three hundred twenty-three".