28170920 has 64 divisors (see below), whose sum is σ = 67564800. Its totient is φ = 10540800.

The previous prime is 28170917. The next prime is 28170937. The reversal of 28170920 is 2907182.

28170920 = 73² + 74² + ... + 439².

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 76577 + ... + 76943.

It is an arithmetic number, because the mean of its divisors is an integer number (1055700).

Almost surely, 2^28170920 is an apocalyptic number.

28170920 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 28170920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33782400).

28170920 is an abundant number, since it is smaller than the sum of its proper divisors (39393880).

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

28170920 is a wasteful number, since it uses less digits than its factorization.

28170920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 498 (or 494 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 29.

The square root of 28170920 is about 5307.6284723029. The cubic root of 28170920 is about 304.2755177643.

It can be divided in two parts, 28170 and 920, that multiplied together give a triangular number (25916400 = T₇₁₉₉).

The spelling of 28170920 in words is "twenty-eight million, one hundred seventy thousand, nine hundred twenty".