21942238091 has 4 divisors (see below), whose sum is σ = 21942593400. Its totient is φ = 21941882784.

The previous prime is 21942238067. The next prime is 21942238117. The reversal of 21942238091 is 19083224912.

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-21942238091 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21942238051) 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, 58286 + ... + 217443.

It is an arithmetic number, because the mean of its divisors is an integer number (5485648350).

Almost surely, 2^21942238091 is an apocalyptic number.

21942238091 is a deficient number, since it is larger than the sum of its proper divisors (355309).

21942238091 is an equidigital number, since it uses as much as digits as its factorization.

21942238091 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 355308.

The product of its (nonzero) digits is 62208, while the sum is 41.

The spelling of 21942238091 in words is "twenty-one billion, nine hundred forty-two million, two hundred thirty-eight thousand, ninety-one".