28117830 has 64 divisors (see below), whose sum is σ = 76966848. Its totient is φ = 6512640.

The previous prime is 28117819. The next prime is 28117871. The reversal of 28117830 is 3871182.

It is a happy number.

It is a super-2 number, since 2×28117830² = 1581224727817800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4510 + ... + 8750.

It is an arithmetic number, because the mean of its divisors is an integer number (1202607).

Almost surely, 2^28117830 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 28117830, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38483424).

28117830 is an abundant number, since it is smaller than the sum of its proper divisors (48849018).

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

28117830 is a wasteful number, since it uses less digits than its factorization.

28117830 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4281.

The product of its (nonzero) digits is 2688, while the sum is 30.

The square root of 28117830 is about 5302.6248217274. The cubic root of 28117830 is about 304.0842549818.

The spelling of 28117830 in words is "twenty-eight million, one hundred seventeen thousand, eight hundred thirty".