21764016 has 60 divisors (see below), whose sum is σ = 61223760. Its totient is φ = 7217280.

The previous prime is 21763999. The next prime is 21764021. The reversal of 21764016 is 61046712.

21764016 is a `hidden beast` number, since 2 + 1 + 7 + 640 + 16 = 666.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 51486 + ... + 51906.

It is an arithmetic number, because the mean of its divisors is an integer number (1020396).

Almost surely, 2^21764016 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21764016, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30611880).

21764016 is an abundant number, since it is smaller than the sum of its proper divisors (39459744).

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

21764016 is a wasteful number, since it uses less digits than its factorization.

21764016 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 794 (or 785 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 27.

The square root of 21764016 is about 4665.1919574654. The cubic root of 21764016 is about 279.1984559428.

The spelling of 21764016 in words is "twenty-one million, seven hundred sixty-four thousand, sixteen".