20720808 has 24 divisors (see below), whose sum is σ = 56119050. Its totient is φ = 6906912.

The previous prime is 20720789. The next prime is 20720893. The reversal of 20720808 is 80802702.

It can be written as a sum of positive squares in only one way, i.e., 13527684 + 7193124 = 3678^2 + 2682^2 .

It is a tau number, because it is divible by the number of its divisors (24).

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 5 ways as a sum of consecutive naturals, for example, 143823 + ... + 143966.

Almost surely, 2^20720808 is an apocalyptic number.

It is an amenable number.

20720808 is an abundant number, since it is smaller than the sum of its proper divisors (35398242).

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

20720808 is a wasteful number, since it uses less digits than its factorization.

20720808 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 287801 (or 287794 counting only the distinct ones).

The product of its (nonzero) digits is 1792, while the sum is 27.

The square root of 20720808 is about 4552.0114235358. The cubic root of 20720808 is about 274.6643088475.

It can be divided in two parts, 20720 and 808, that added together give a triangular number (21528 = T₂₀₇).

The spelling of 20720808 in words is "twenty million, seven hundred twenty thousand, eight hundred eight".