20191816 has 16 divisors (see below), whose sum is σ = 38150640. Its totient is φ = 10018320.

The previous prime is 20191799. The next prime is 20191841. The reversal of 20191816 is 61819102.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8586 + ... + 10681.

It is an arithmetic number, because the mean of its divisors is an integer number (2384415).

Almost surely, 2^20191816 is an apocalyptic number.

It is an amenable number.

20191816 is a deficient number, since it is larger than the sum of its proper divisors (17958824).

20191816 is a wasteful number, since it uses less digits than its factorization.

20191816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19404 (or 19400 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 28.

The square root of 20191816 is about 4493.5304605622. The cubic root of 20191816 is about 272.3067833246.

The spelling of 20191816 in words is "twenty million, one hundred ninety-one thousand, eight hundred sixteen".