20081816 has 8 divisors (see below), whose sum is σ = 37653420. Its totient is φ = 10040904.

The previous prime is 20081797. The next prime is 20081821. The reversal of 20081816 is 61818002.

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

It is a congruent number.

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 as a sum of consecutive naturals, namely, 1255106 + ... + 1255121.

Almost surely, 2^20081816 is an apocalyptic number.

It is an amenable number.

20081816 is a deficient number, since it is larger than the sum of its proper divisors (17571604).

20081816 is a wasteful number, since it uses less digits than its factorization.

20081816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2510233 (or 2510229 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 26.

The square root of 20081816 is about 4481.2739260170. The cubic root of 20081816 is about 271.8113960695.

Adding to 20081816 its reverse (61818002), we get a palindrome (81899818).

The spelling of 20081816 in words is "twenty million, eighty-one thousand, eight hundred sixteen".