21100289 has 8 divisors (see below), whose sum is σ = 24221760. Its totient is φ = 18005616.

The previous prime is 21100267. The next prime is 21100297. The reversal of 21100289 is 98200112.

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 21100289 - 2⁸ = 21100033 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21100489) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4979 + ... + 8184.

It is an arithmetic number, because the mean of its divisors is an integer number (3027720).

Almost surely, 2^21100289 is an apocalyptic number.

It is an amenable number.

21100289 is a deficient number, since it is larger than the sum of its proper divisors (3121471).

21100289 is a wasteful number, since it uses less digits than its factorization.

21100289 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13399.

The product of its (nonzero) digits is 288, while the sum is 23.

The square root of 21100289 is about 4593.5050887095. The cubic root of 21100289 is about 276.3309104195.

The spelling of 21100289 in words is "twenty-one million, one hundred thousand, two hundred eighty-nine".