21201120191 has 4 divisors (see below), whose sum is σ = 21203102592. Its totient is φ = 21199137792.

The previous prime is 21201120179. The next prime is 21201120197. The reversal of 21201120191 is 19102110212.

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 21201120191 - 2²² = 21196925887 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21201120197) 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, 975071 + ... + 996576.

It is an arithmetic number, because the mean of its divisors is an integer number (5300775648).

Almost surely, 2^21201120191 is an apocalyptic number.

21201120191 is a deficient number, since it is larger than the sum of its proper divisors (1982401).

21201120191 is a wasteful number, since it uses less digits than its factorization.

21201120191 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1982400.

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

The spelling of 21201120191 in words is "twenty-one billion, two hundred one million, one hundred twenty thousand, one hundred ninety-one".