20807816 has 8 divisors (see below), whose sum is σ = 39014670. Its totient is φ = 10403904.

The previous prime is 20807803. The next prime is 20807833. The reversal of 20807816 is 61870802.

It can be written as a sum of positive squares in only one way, i.e., 13764100 + 7043716 = 3710^2 + 2654^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1300481 + ... + 1300496.

Almost surely, 2^20807816 is an apocalyptic number.

It is an amenable number.

20807816 is a deficient number, since it is larger than the sum of its proper divisors (18206854).

20807816 is a wasteful number, since it uses less digits than its factorization.

20807816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2600983 (or 2600979 counting only the distinct ones).

The product of its (nonzero) digits is 5376, while the sum is 32.

The square root of 20807816 is about 4561.5585055987. The cubic root of 20807816 is about 275.0482163390.

The spelling of 20807816 in words is "twenty million, eight hundred seven thousand, eight hundred sixteen".