21201112091 has 4 divisors (see below), whose sum is σ = 21355864872. Its totient is φ = 21046359312.

The previous prime is 21201112087. The next prime is 21201112139. The reversal of 21201112091 is 19021110212.

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 21201112091 - 2² = 21201112087 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21201112081) 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, 77376185 + ... + 77376458.

It is an arithmetic number, because the mean of its divisors is an integer number (5338966218).

Almost surely, 2^21201112091 is an apocalyptic number.

21201112091 is a deficient number, since it is larger than the sum of its proper divisors (154752781).

21201112091 is a wasteful number, since it uses less digits than its factorization.

21201112091 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 154752780.

The product of its (nonzero) digits is 72, while the sum is 20.

The spelling of 21201112091 in words is "twenty-one billion, two hundred one million, one hundred twelve thousand, ninety-one".