21321315269 has 4 divisors (see below), whose sum is σ = 21321619500. Its totient is φ = 21321011040.

The previous prime is 21321315259. The next prime is 21321315277. The reversal of 21321315269 is 96251312312.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 1357038244 + 19964277025 = 36838^2 + 141295^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21321315269 is a prime.

It is a super-2 number, since 2×21321315269² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21321315209) 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, 12107 + ... + 206855.

It is an arithmetic number, because the mean of its divisors is an integer number (5330404875).

Almost surely, 2^21321315269 is an apocalyptic number.

It is an amenable number.

21321315269 is a deficient number, since it is larger than the sum of its proper divisors (304231).

21321315269 is a wasteful number, since it uses less digits than its factorization.

21321315269 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 304230.

The product of its digits is 19440, while the sum is 35.

The spelling of 21321315269 in words is "twenty-one billion, three hundred twenty-one million, three hundred fifteen thousand, two hundred sixty-nine".