20090805 has 16 divisors (see below), whose sum is σ = 36737664. Its totient is φ = 9184320.

The previous prime is 20090801. The next prime is 20090813. The reversal of 20090805 is 50809002.

It is not a de Polignac number, because 20090805 - 2² = 20090801 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20090801) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 95566 + ... + 95775.

It is an arithmetic number, because the mean of its divisors is an integer number (2296104).

Almost surely, 2^20090805 is an apocalyptic number.

It is an amenable number.

20090805 is a deficient number, since it is larger than the sum of its proper divisors (16646859).

20090805 is a wasteful number, since it uses less digits than its factorization.

20090805 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 191356.

The product of its (nonzero) digits is 720, while the sum is 24.

The square root of 20090805 is about 4482.2767652165. The cubic root of 20090805 is about 271.8519459907.

Adding to 20090805 its reverse (50809002), we get a palindrome (70899807).

The spelling of 20090805 in words is "twenty million, ninety thousand, eight hundred five".