28787918 has 4 divisors (see below), whose sum is σ = 43181880. Its totient is φ = 14393958.

The previous prime is 28787917. The next prime is 28787921. The reversal of 28787918 is 81978782.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28787911) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7196978 + ... + 7196981.

It is an arithmetic number, because the mean of its divisors is an integer number (10795470).

Almost surely, 2^28787918 is an apocalyptic number.

28787918 is a deficient number, since it is larger than the sum of its proper divisors (14393962).

28787918 is a wasteful number, since it uses less digits than its factorization.

28787918 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14393961.

The product of its digits is 451584, while the sum is 50.

The square root of 28787918 is about 5365.4373540281. The cubic root of 28787918 is about 306.4809033020.

The spelling of 28787918 in words is "twenty-eight million, seven hundred eighty-seven thousand, nine hundred eighteen".