21082816 has 14 divisors (see below), whose sum is σ = 41836340. Its totient is φ = 10541376.

The previous prime is 21082807. The next prime is 21082819. The reversal of 21082816 is 61828012.

It is not an unprimeable number, because it can be changed into a prime (21082819) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 164646 + ... + 164773.

It is an arithmetic number, because the mean of its divisors is an integer number (2988310).

Almost surely, 2^21082816 is an apocalyptic number.

It is an amenable number.

21082816 is a deficient number, since it is larger than the sum of its proper divisors (20753524).

21082816 is an equidigital number, since it uses as much as digits as its factorization.

21082816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 329431 (or 329421 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 28.

The square root of 21082816 is about 4591.6027702753. The cubic root of 21082816 is about 276.2546134649.

The spelling of 21082816 in words is "twenty-one million, eighty-two thousand, eight hundred sixteen".