21280191 has 8 divisors (see below), whose sum is σ = 28773504. Its totient is φ = 13986840.

The previous prime is 21280177. The next prime is 21280201. The reversal of 21280191 is 19108212.

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

It is not a de Polignac number, because 21280191 - 2⁵ = 21280159 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21280691) 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, 49741 + ... + 50166.

It is an arithmetic number, because the mean of its divisors is an integer number (3596688).

Almost surely, 2^21280191 is an apocalyptic number.

21280191 is a deficient number, since it is larger than the sum of its proper divisors (7493313).

21280191 is an equidigital number, since it uses as much as digits as its factorization.

21280191 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 99981.

The product of its (nonzero) digits is 288, while the sum is 24.

The square root of 21280191 is about 4613.0457400724. The cubic root of 21280191 is about 277.1140255271.

The spelling of 21280191 in words is "twenty-one million, two hundred eighty thousand, one hundred ninety-one".