21939978327 has 4 divisors (see below), whose sum is σ = 29253304440. Its totient is φ = 14626652216.

The previous prime is 21939978317. The next prime is 21939978329. The reversal of 21939978327 is 72387993912.

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 21939978327 - 2²⁶ = 21872869463 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21939978329) 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, 3656663052 + ... + 3656663057.

It is an arithmetic number, because the mean of its divisors is an integer number (7313326110).

Almost surely, 2^21939978327 is an apocalyptic number.

21939978327 is a deficient number, since it is larger than the sum of its proper divisors (7313326113).

21939978327 is an equidigital number, since it uses as much as digits as its factorization.

21939978327 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7313326112.

The product of its digits is 10287648, while the sum is 60.

The spelling of 21939978327 in words is "twenty-one billion, nine hundred thirty-nine million, nine hundred seventy-eight thousand, three hundred twenty-seven".