28781107 has 4 divisors (see below), whose sum is σ = 28797480. Its totient is φ = 28764736.

The previous prime is 28781101. The next prime is 28781141. The reversal of 28781107 is 70118782.

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

It is a cyclic number.

It is not a de Polignac number, because 28781107 - 2³ = 28781099 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28781101) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5182 + ... + 9187.

It is an arithmetic number, because the mean of its divisors is an integer number (7199370).

Almost surely, 2^28781107 is an apocalyptic number.

28781107 is a deficient number, since it is larger than the sum of its proper divisors (16373).

28781107 is a wasteful number, since it uses less digits than its factorization.

28781107 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16372.

The product of its (nonzero) digits is 6272, while the sum is 34.

The square root of 28781107 is about 5364.8026058747. The cubic root of 28781107 is about 306.4567310541.

Adding to 28781107 its reverse (70118782), we get a palindrome (98899889).

The spelling of 28781107 in words is "twenty-eight million, seven hundred eighty-one thousand, one hundred seven".