21391281326 has 4 divisors (see below), whose sum is σ = 32086921992. Its totient is φ = 10695640662.

The previous prime is 21391281299. The next prime is 21391281341. The reversal of 21391281326 is 62318219312.

It is a semiprime because it is the product of two primes.

It is a self number, because there is not a number n which added to its sum of digits gives 21391281326.

It is a congruent number.

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 5347820330 + ... + 5347820333.

It is an arithmetic number, because the mean of its divisors is an integer number (8021730498).

Almost surely, 2^21391281326 is an apocalyptic number.

21391281326 is a deficient number, since it is larger than the sum of its proper divisors (10695640666).

21391281326 is a wasteful number, since it uses less digits than its factorization.

21391281326 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10695640665.

The product of its digits is 31104, while the sum is 38.

The spelling of 21391281326 in words is "twenty-one billion, three hundred ninety-one million, two hundred eighty-one thousand, three hundred twenty-six".