21059871 has 8 divisors (see below), whose sum is σ = 32091264. Its totient is φ = 12034200.

The previous prime is 21059867. The next prime is 21059879. The reversal of 21059871 is 17895012.

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

It is not a de Polignac number, because 21059871 - 2² = 21059867 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21059879) 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, 501405 + ... + 501446.

It is an arithmetic number, because the mean of its divisors is an integer number (4011408).

Almost surely, 2^21059871 is an apocalyptic number.

21059871 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

21059871 is a deficient number, since it is larger than the sum of its proper divisors (11031393).

21059871 is a wasteful number, since it uses less digits than its factorization.

21059871 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1002861.

The product of its (nonzero) digits is 5040, while the sum is 33.

The square root of 21059871 is about 4589.1035072223. The cubic root of 21059871 is about 276.1543586252.

The spelling of 21059871 in words is "twenty-one million, fifty-nine thousand, eight hundred seventy-one".