20717928 has 192 divisors, whose sum is σ = 72558720. Its totient is φ = 5184000.

The previous prime is 20717927. The next prime is 20717947. The reversal of 20717928 is 82971702.

It is a super-2 number, since 2×20717928² = 858465081226368, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 20717892 and 20717901.

It is not an unprimeable number, because it can be changed into a prime (20717927) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 205078 + ... + 205178.

It is an arithmetic number, because the mean of its divisors is an integer number (377910).

Almost surely, 2^20717928 is an apocalyptic number.

20717928 is a gapful number since it is divisible by the number (28) 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 20717928, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36279360).

20717928 is an abundant number, since it is smaller than the sum of its proper divisors (51840792).

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

20717928 is a wasteful number, since it uses less digits than its factorization.

20717928 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 168 (or 161 counting only the distinct ones).

The product of its (nonzero) digits is 14112, while the sum is 36.

The square root of 20717928 is about 4551.6950688727. The cubic root of 20717928 is about 274.6515829946.

It can be divided in two parts, 2071 and 7928, that added together give a palindrome (9999).

The spelling of 20717928 in words is "twenty million, seven hundred seventeen thousand, nine hundred twenty-eight".