20805031 has 4 divisors (see below), whose sum is σ = 22405432. Its totient is φ = 19204632.

The previous prime is 20805017. The next prime is 20805047. The reversal of 20805031 is 13050802.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20805031 - 2¹¹ = 20802983 is a prime.

It is a super-2 number, since 2×20805031² = 865698629821922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20805011) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 800181 + ... + 800206.

It is an arithmetic number, because the mean of its divisors is an integer number (5601358).

Almost surely, 2^20805031 is an apocalyptic number.

20805031 is a deficient number, since it is larger than the sum of its proper divisors (1600401).

20805031 is a wasteful number, since it uses less digits than its factorization.

20805031 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1600400.

The product of its (nonzero) digits is 240, while the sum is 19.

The square root of 20805031 is about 4561.2532269103. The cubic root of 20805031 is about 275.0359446129.

Adding to 20805031 its reverse (13050802), we get a palindrome (33855833).

The spelling of 20805031 in words is "twenty million, eight hundred five thousand, thirty-one".