20728808 has 16 divisors (see below), whose sum is σ = 39009060. Its totient is φ = 10326400.

The previous prime is 20728787. The next prime is 20728811. The reversal of 20728808 is 80882702.

It can be written as a sum of positive squares in 2 ways, for example, as 18472804 + 2256004 = 4298^2 + 1502^2 .

It is a super-2 number, since 2×20728808² = 859366962201728, which contains 22 as substring.

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 3 ways as a sum of consecutive naturals, for example, 2363 + ... + 6858.

Almost surely, 2^20728808 is an apocalyptic number.

It is an amenable number.

20728808 is a deficient number, since it is larger than the sum of its proper divisors (18280252).

20728808 is a wasteful number, since it uses less digits than its factorization.

20728808 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9508 (or 9504 counting only the distinct ones).

The product of its (nonzero) digits is 14336, while the sum is 35.

The square root of 20728808 is about 4552.8900711526. The cubic root of 20728808 is about 274.6996522528.

The spelling of 20728808 in words is "twenty million, seven hundred twenty-eight thousand, eight hundred eight".