20171928 has 96 divisors (see below), whose sum is σ = 62175600. Its totient is φ = 5419008.

The previous prime is 20171927. The next prime is 20171929. The reversal of 20171928 is 82917102.

It is an interprime number because it is at equal distance from previous prime (20171927) and next prime (20171929).

It is a hoax number, since the sum of its digits (30) coincides with the sum of the digits of its distinct prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 20171895 and 20171904.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20171927) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 19488 + ... + 20496.

Almost surely, 2^20171928 is an apocalyptic number.

20171928 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 20171928, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31087800).

20171928 is an abundant number, since it is smaller than the sum of its proper divisors (42003672).

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

20171928 is a wasteful number, since it uses less digits than its factorization.

20171928 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1049 (or 1038 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 30.

The square root of 20171928 is about 4491.3169560831. The cubic root of 20171928 is about 272.2173507821.

The spelling of 20171928 in words is "twenty million, one hundred seventy-one thousand, nine hundred twenty-eight".