20631205 has 24 divisors (see below), whose sum is σ = 29105568. Its totient is φ = 13997088.

The previous prime is 20631203. The next prime is 20631229. The reversal of 20631205 is 50213602.

It is a happy number.

It is not a de Polignac number, because 20631205 - 2¹ = 20631203 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20631203) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 25822 + ... + 26608.

It is an arithmetic number, because the mean of its divisors is an integer number (1212732).

Almost surely, 2^20631205 is an apocalyptic number.

It is an amenable number.

20631205 is a deficient number, since it is larger than the sum of its proper divisors (8474363).

20631205 is a wasteful number, since it uses less digits than its factorization.

20631205 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 913 (or 906 counting only the distinct ones).

The product of its (nonzero) digits is 360, while the sum is 19.

The square root of 20631205 is about 4542.1586277892. The cubic root of 20631205 is about 274.2678264598.

Adding to 20631205 its reverse (50213602), we get a palindrome (70844807).

The spelling of 20631205 in words is "twenty million, six hundred thirty-one thousand, two hundred five".