20640222 has 12 divisors (see below), whose sum is σ = 44720520. Its totient is φ = 6880068.

The previous prime is 20640181. The next prime is 20640233. The reversal of 20640222 is 22204602.

It is a happy number.

20640222 is a `hidden beast` number, since 2 + 0 + 640 + 2 + 22 = 666.

It is a Harshad number since it is a multiple of its sum of digits (18), and also a Moran number because the ratio is a prime number: 1146679 = 20640222 / (2 + 0 + 6 + 4 + 0 + 2 + 2 + 2).

It is a junction number, because it is equal to n+sod(n) for n = 20640195 and 20640204.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 573322 + ... + 573357.

It is an arithmetic number, because the mean of its divisors is an integer number (3726710).

Almost surely, 2^20640222 is an apocalyptic number.

20640222 is an abundant number, since it is smaller than the sum of its proper divisors (24080298).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20640222 is a wasteful number, since it uses less digits than its factorization.

20640222 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1146687 (or 1146684 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 18.

The square root of 20640222 is about 4543.1511090872. The cubic root of 20640222 is about 274.3077774756.

Adding to 20640222 its reverse (22204602), we get a palindrome (42844824).

The spelling of 20640222 in words is "twenty million, six hundred forty thousand, two hundred twenty-two".