21071008 has 48 divisors (see below), whose sum is σ = 47900160. Its totient is φ = 8937216.

The previous prime is 21071003. The next prime is 21071009. The reversal of 21071008 is 80017012.

It is not an unprimeable number, because it can be changed into a prime (21071003) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 23985 + ... + 24847.

It is an arithmetic number, because the mean of its divisors is an integer number (997920).

Almost surely, 2^21071008 is an apocalyptic number.

21071008 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21071008, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23950080).

21071008 is an abundant number, since it is smaller than the sum of its proper divisors (26829152).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21071008 is a wasteful number, since it uses less digits than its factorization.

21071008 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 989 (or 981 counting only the distinct ones).

The product of its (nonzero) digits is 112, while the sum is 19.

The square root of 21071008 is about 4590.3167646689. The cubic root of 21071008 is about 276.2030292164.

The spelling of 21071008 in words is "twenty-one million, seventy-one thousand, eight".