20820172 has 24 divisors (see below), whose sum is σ = 38779776. Its totient is φ = 9746688.

The previous prime is 20820161. The next prime is 20820179. The reversal of 20820172 is 27102802.

It is not an unprimeable number, because it can be changed into a prime (20820179) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 14478 + ... + 15850.

It is an arithmetic number, because the mean of its divisors is an integer number (1615824).

Almost surely, 2^20820172 is an apocalyptic number.

It is an amenable number.

20820172 is a deficient number, since it is larger than the sum of its proper divisors (17959604).

20820172 is a wasteful number, since it uses less digits than its factorization.

20820172 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1617 (or 1615 counting only the distinct ones).

The product of its (nonzero) digits is 448, while the sum is 22.

The square root of 20820172 is about 4562.9126662692. The cubic root of 20820172 is about 275.1026481815.

Adding to 20820172 its reverse (27102802), we get a palindrome (47922974).

The spelling of 20820172 in words is "twenty million, eight hundred twenty thousand, one hundred seventy-two".