21179871 has 24 divisors (see below), whose sum is σ = 31414656. Its totient is φ = 13746240.

The previous prime is 21179869. The next prime is 21179891. The reversal of 21179871 is 17897112.

It is not a de Polignac number, because 21179871 - 2¹ = 21179869 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21179861) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 94866 + ... + 95088.

It is an arithmetic number, because the mean of its divisors is an integer number (1308944).

Almost surely, 2^21179871 is an apocalyptic number.

21179871 is a deficient number, since it is larger than the sum of its proper divisors (10234785).

21179871 is a wasteful number, since it uses less digits than its factorization.

21179871 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 463 (or 460 counting only the distinct ones).

The product of its digits is 7056, while the sum is 36.

The square root of 21179871 is about 4602.1593844629. The cubic root of 21179871 is about 276.6778784508.

The spelling of 21179871 in words is "twenty-one million, one hundred seventy-nine thousand, eight hundred seventy-one".