28329987 has 18 divisors (see below), whose sum is σ = 44040708. Its totient is φ = 16151688.

The previous prime is 28329967. The next prime is 28330009. The reversal of 28329987 is 78992382.

It is a happy number.

It is not a de Polignac number, because 28329987 - 2¹¹ = 28327939 is a prime.

It is not an unprimeable number, because it can be changed into a prime (28329907) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 64314 + ... + 64752.

It is an arithmetic number, because the mean of its divisors is an integer number (2446706).

Almost surely, 2^28329987 is an apocalyptic number.

28329987 is a deficient number, since it is larger than the sum of its proper divisors (15710721).

28329987 is an frugal number, since it uses more digits than its factorization.

28329987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 895 (or 449 counting only the distinct ones).

The product of its digits is 435456, while the sum is 48.

The square root of 28329987 is about 5322.5921316592. The cubic root of 28329987 is about 304.8471401005.

Multiplying 28329987 by its sum of digits (48), we get a square (1359839376 = 36876²).

The spelling of 28329987 in words is "twenty-eight million, three hundred twenty-nine thousand, nine hundred eighty-seven".