21201022191 has 8 divisors (see below), whose sum is σ = 28268863920. Its totient is φ = 14133597632.

The previous prime is 21201022147. The next prime is 21201022229. The reversal of 21201022191 is 19122010212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21201022191 - 2⁹ = 21201021679 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21201022691) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 44701 + ... + 210713.

It is an arithmetic number, because the mean of its divisors is an integer number (3533607990).

Almost surely, 2^21201022191 is an apocalyptic number.

21201022191 is a deficient number, since it is larger than the sum of its proper divisors (7067841729).

21201022191 is a wasteful number, since it uses less digits than its factorization.

21201022191 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 208585.

The product of its (nonzero) digits is 144, while the sum is 21.

The spelling of 21201022191 in words is "twenty-one billion, two hundred one million, twenty-two thousand, one hundred ninety-one".