28711987 has 4 divisors (see below), whose sum is σ = 28744416. Its totient is φ = 28679560.

The previous prime is 28711967. The next prime is 28711993. The reversal of 28711987 is 78911782.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 78911782 = 2 ⋅39455891.

It is a cyclic number.

It is not a de Polignac number, because 28711987 - 2¹⁵ = 28679219 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28711957) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14848 + ... + 16669.

It is an arithmetic number, because the mean of its divisors is an integer number (7186104).

Almost surely, 2^28711987 is an apocalyptic number.

28711987 is a deficient number, since it is larger than the sum of its proper divisors (32429).

28711987 is an equidigital number, since it uses as much as digits as its factorization.

28711987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32428.

The product of its digits is 56448, while the sum is 43.

The square root of 28711987 is about 5358.3567443760. The cubic root of 28711987 is about 306.2112080811.

The spelling of 28711987 in words is "twenty-eight million, seven hundred eleven thousand, nine hundred eighty-seven".