21552871 has 4 divisors (see below), whose sum is σ = 21642544. Its totient is φ = 21463200.

The previous prime is 21552851. The next prime is 21552893. The reversal of 21552871 is 17825512.

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 21552871 - 2²¹ = 19455719 is a prime.

It is a Duffinian number.

It is a zygodrome in base 3.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21552841) 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, 44475 + ... + 44956.

It is an arithmetic number, because the mean of its divisors is an integer number (5410636).

Almost surely, 2^21552871 is an apocalyptic number.

21552871 is a deficient number, since it is larger than the sum of its proper divisors (89673).

21552871 is an equidigital number, since it uses as much as digits as its factorization.

21552871 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 89672.

The product of its digits is 5600, while the sum is 31.

The square root of 21552871 is about 4642.5069736081. The cubic root of 21552871 is about 278.2926330422.

The spelling of 21552871 in words is "twenty-one million, five hundred fifty-two thousand, eight hundred seventy-one".