28381830 has 32 divisors (see below), whose sum is σ = 68387328. Its totient is φ = 7538400.

The previous prime is 28381819. The next prime is 28381831. The reversal of 28381830 is 3818382.

It is a junction number, because it is equal to n+sod(n) for n = 28381791 and 28381800.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28381831) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6385 + ... + 9875.

It is an arithmetic number, because the mean of its divisors is an integer number (2137104).

Almost surely, 2^28381830 is an apocalyptic number.

28381830 is an abundant number, since it is smaller than the sum of its proper divisors (40005498).

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

28381830 is a wasteful number, since it uses less digits than its factorization.

28381830 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3772.

The product of its (nonzero) digits is 9216, while the sum is 33.

The square root of 28381830 is about 5327.4599951572. The cubic root of 28381830 is about 305.0329803985.

The spelling of 28381830 in words is "twenty-eight million, three hundred eighty-one thousand, eight hundred thirty".