21155867323 has 4 divisors (see below), whose sum is σ = 21838314688. Its totient is φ = 20473419960.

The previous prime is 21155867287. The next prime is 21155867329. The reversal of 21155867323 is 32376855112.

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-21155867323 is a prime.

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 21155867323.

It is not an unprimeable number, because it can be changed into a prime (21155867329) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 341223636 + ... + 341223697.

It is an arithmetic number, because the mean of its divisors is an integer number (5459578672).

Almost surely, 2^21155867323 is an apocalyptic number.

21155867323 is a deficient number, since it is larger than the sum of its proper divisors (682447365).

21155867323 is an equidigital number, since it uses as much as digits as its factorization.

21155867323 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 682447364.

The product of its digits is 302400, while the sum is 43.

The spelling of 21155867323 in words is "twenty-one billion, one hundred fifty-five million, eight hundred sixty-seven thousand, three hundred twenty-three".