28177920 has 120 divisors (see below), whose sum is σ = 97667856. Its totient is φ = 7507968.

The previous prime is 28177909. The next prime is 28177939. The reversal of 28177920 is 2977182.

It is a tau number, because it is divible by the number of its divisors (120).

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 22429 + ... + 23651.

Almost surely, 2^28177920 is an apocalyptic number.

28177920 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 28177920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (48833928).

28177920 is an abundant number, since it is smaller than the sum of its proper divisors (69489936).

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

28177920 is a wasteful number, since it uses less digits than its factorization.

28177920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1252 (or 1233 counting only the distinct ones).

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

The square root of 28177920 is about 5308.2878595645. The cubic root of 28177920 is about 304.3007181274.

The spelling of 28177920 in words is "twenty-eight million, one hundred seventy-seven thousand, nine hundred twenty".