20617220 has 48 divisors (see below), whose sum is σ = 46992960. Its totient is φ = 7552896.

The previous prime is 20617213. The next prime is 20617229. The reversal of 20617220 is 2271602.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 20617192 and 20617201.

It is not an unprimeable number, because it can be changed into a prime (20617229) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 46319 + ... + 46761.

It is an arithmetic number, because the mean of its divisors is an integer number (979020).

Almost surely, 2^20617220 is an apocalyptic number.

20617220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20617220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23496480).

20617220 is an abundant number, since it is smaller than the sum of its proper divisors (26375740).

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

20617220 is a wasteful number, since it uses less digits than its factorization.

20617220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 644 (or 642 counting only the distinct ones).

The product of its (nonzero) digits is 336, while the sum is 20.

The square root of 20617220 is about 4540.6189005465. The cubic root of 20617220 is about 274.2058410264.

Adding to 20617220 its reverse (2271602), we get a palindrome (22888822).

The spelling of 20617220 in words is "twenty million, six hundred seventeen thousand, two hundred twenty".