21067776 has 120 divisors (see below), whose sum is σ = 63423360. Its totient is φ = 6967296.

The previous prime is 21067769. The next prime is 21067801. The reversal of 21067776 is 67776012.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 21067776.

It is a congruent number.

It is an unprimeable number.

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 9 ways as a sum of consecutive naturals, for example, 165825 + ... + 165951.

It is an arithmetic number, because the mean of its divisors is an integer number (528528).

Almost surely, 2^21067776 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 21067776, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31711680).

21067776 is an abundant number, since it is smaller than the sum of its proper divisors (42355584).

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

21067776 is an equidigital number, since it uses as much as digits as its factorization.

21067776 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 161 (or 132 counting only the distinct ones).

The product of its (nonzero) digits is 24696, while the sum is 36.

The square root of 21067776 is about 4589.9647057467. The cubic root of 21067776 is about 276.1889065913.

The spelling of 21067776 in words is "twenty-one million, sixty-seven thousand, seven hundred seventy-six".