20405212 has 24 divisors (see below), whose sum is σ = 37648800. Its totient is φ = 9662016.

The previous prime is 20405207. The next prime is 20405213. The reversal of 20405212 is 21250402.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20405213) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4489 + ... + 7807.

It is an arithmetic number, because the mean of its divisors is an integer number (1568700).

Almost surely, 2^20405212 is an apocalyptic number.

It is an amenable number.

20405212 is a deficient number, since it is larger than the sum of its proper divisors (17243588).

20405212 is a wasteful number, since it uses less digits than its factorization.

20405212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3405 (or 3403 counting only the distinct ones).

The product of its (nonzero) digits is 160, while the sum is 16.

The square root of 20405212 is about 4517.2128575041. The cubic root of 20405212 is about 273.2627096275.

Adding to 20405212 its reverse (21250402), we get a palindrome (41655614).

The spelling of 20405212 in words is "twenty million, four hundred five thousand, two hundred twelve".