21016568 has 32 divisors (see below), whose sum is σ = 40383360. Its totient is φ = 10251360.

The previous prime is 21016547. The next prime is 21016577. The reversal of 21016568 is 86561012.

It is a happy number.

It is a super-2 number, since 2×21016568² = 883392260997248, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21016568.

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 92471 + ... + 92697.

It is an arithmetic number, because the mean of its divisors is an integer number (1261980).

Almost surely, 2^21016568 is an apocalyptic number.

It is an amenable number.

21016568 is a deficient number, since it is larger than the sum of its proper divisors (19366792).

21016568 is a wasteful number, since it uses less digits than its factorization.

21016568 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 467 (or 463 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 29.

The square root of 21016568 is about 4584.3830555485. The cubic root of 21016568 is about 275.9649538922.

It can be divided in two parts, 2 and 1016568, that multiplied together give a triangular number (2033136 = T₂₀₁₆).

The spelling of 21016568 in words is "twenty-one million, sixteen thousand, five hundred sixty-eight".