28139994 has 64 divisors (see below), whose sum is σ = 66124800. Its totient is φ = 8852976.

The previous prime is 28139987. The next prime is 28139999. The reversal of 28139994 is 49993182.

It is not an unprimeable number, because it can be changed into a prime (28139999) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 172557 + ... + 172719.

It is an arithmetic number, because the mean of its divisors is an integer number (1033200).

Almost surely, 2^28139994 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 28139994, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33062400).

28139994 is an abundant number, since it is smaller than the sum of its proper divisors (37984806).

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

28139994 is a wasteful number, since it uses less digits than its factorization.

28139994 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 336 (or 330 counting only the distinct ones).

The product of its digits is 139968, while the sum is 45.

The square root of 28139994 is about 5304.7143184153. The cubic root of 28139994 is about 304.1641325700.

The spelling of 28139994 in words is "twenty-eight million, one hundred thirty-nine thousand, nine hundred ninety-four".