21159055 has 4 divisors (see below), whose sum is σ = 25390872. Its totient is φ = 16927240.

The previous prime is 21159041. The next prime is 21159059. The reversal of 21159055 is 55095112.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 21159055 - 2¹³ = 21150863 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 (21159059) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2115901 + ... + 2115910.

It is an arithmetic number, because the mean of its divisors is an integer number (6347718).

Almost surely, 2^21159055 is an apocalyptic number.

21159055 is a deficient number, since it is larger than the sum of its proper divisors (4231817).

21159055 is an equidigital number, since it uses as much as digits as its factorization.

21159055 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4231816.

The product of its (nonzero) digits is 2250, while the sum is 28.

The square root of 21159055 is about 4599.8972814618. The cubic root of 21159055 is about 276.5872072259.

The spelling of 21159055 in words is "twenty-one million, one hundred fifty-nine thousand, fifty-five".