20640210 has 32 divisors (see below), whose sum is σ = 52451712. Its totient is φ = 5180160.

The previous prime is 20640181. The next prime is 20640233. The reversal of 20640210 is 1204602.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 20640210.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 19726 + ... + 20745.

It is an arithmetic number, because the mean of its divisors is an integer number (1639116).

Almost surely, 2^20640210 is an apocalyptic number.

20640210 is an abundant number, since it is smaller than the sum of its proper divisors (31811502).

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

20640210 is a wasteful number, since it uses less digits than its factorization.

20640210 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40498.

The product of its (nonzero) digits is 96, while the sum is 15.

The square root of 20640210 is about 4543.1497884177. The cubic root of 20640210 is about 274.3077243157.

Adding to 20640210 its reverse (1204602), we get a palindrome (21844812).

The spelling of 20640210 in words is "twenty million, six hundred forty thousand, two hundred ten".