21071568 has 180 divisors, whose sum is σ = 69436032. Its totient is φ = 5483520.

The previous prime is 21071563. The next prime is 21071579. The reversal of 21071568 is 86517012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21071563) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 679713 + ... + 679743.

Almost surely, 2^21071568 is an apocalyptic number.

21071568 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 21071568, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34718016).

21071568 is an abundant number, since it is smaller than the sum of its proper divisors (48364464).

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

21071568 is a wasteful number, since it uses less digits than its factorization.

21071568 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 90 (or 60 counting only the distinct ones).

The product of its (nonzero) digits is 3360, while the sum is 30.

The square root of 21071568 is about 4590.3777622326. The cubic root of 21071568 is about 276.2054760591.

The spelling of 21071568 in words is "twenty-one million, seventy-one thousand, five hundred sixty-eight".