21343540523 has 4 divisors (see below), whose sum is σ = 21345859920. Its totient is φ = 21341221128.

The previous prime is 21343540513. The next prime is 21343540583. The reversal of 21343540523 is 32504534312.

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 21343540523 - 2⁴ = 21343540507 is a prime.

It is a super-2 number, since 2×21343540523² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21343540523.

It is not an unprimeable number, because it can be changed into a prime (21343540513) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1145840 + ... + 1164317.

It is an arithmetic number, because the mean of its divisors is an integer number (5336464980).

Almost surely, 2^21343540523 is an apocalyptic number.

21343540523 is a deficient number, since it is larger than the sum of its proper divisors (2319397).

21343540523 is an equidigital number, since it uses as much as digits as its factorization.

21343540523 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2319396.

The product of its (nonzero) digits is 43200, while the sum is 32.

The spelling of 21343540523 in words is "twenty-one billion, three hundred forty-three million, five hundred forty thousand, five hundred twenty-three".