20816091 has 6 divisors (see below), whose sum is σ = 30067700. Its totient is φ = 13877388.

The previous prime is 20816087. The next prime is 20816099. The reversal of 20816091 is 19061802.

It is not a de Polignac number, because 20816091 - 2² = 20816087 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20816099) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1156441 + ... + 1156458.

Almost surely, 2^20816091 is an apocalyptic number.

20816091 is a deficient number, since it is larger than the sum of its proper divisors (9251609).

20816091 is a wasteful number, since it uses less digits than its factorization.

20816091 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2312905 (or 2312902 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 27.

The square root of 20816091 is about 4562.4654519240. The cubic root of 20816091 is about 275.0846725492.

Adding to 20816091 its reverse (19061802), we get a palindrome (39877893).

The spelling of 20816091 in words is "twenty million, eight hundred sixteen thousand, ninety-one".