21352871 has 4 divisors (see below), whose sum is σ = 21476472. Its totient is φ = 21229272.

The previous prime is 21352861. The next prime is 21352883. The reversal of 21352871 is 17825312.

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 21352871 - 2²² = 17158567 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 (21352801) 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, 61541 + ... + 61886.

It is an arithmetic number, because the mean of its divisors is an integer number (5369118).

Almost surely, 2^21352871 is an apocalyptic number.

21352871 is a deficient number, since it is larger than the sum of its proper divisors (123601).

21352871 is a wasteful number, since it uses less digits than its factorization.

21352871 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 123600.

The product of its digits is 3360, while the sum is 29.

The square root of 21352871 is about 4620.9166839492. The cubic root of 21352871 is about 277.4291505408.

The spelling of 21352871 in words is "twenty-one million, three hundred fifty-two thousand, eight hundred seventy-one".