28687218 has 32 divisors (see below), whose sum is σ = 65729664. Its totient is φ = 8176512.

The previous prime is 28687213. The next prime is 28687223. The reversal of 28687218 is 81278682.

It is an interprime number because it is at equal distance from previous prime (28687213) and next prime (28687223).

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 28687218.

It is not an unprimeable number, because it can be changed into a prime (28687213) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 33046 + ... + 33902.

It is an arithmetic number, because the mean of its divisors is an integer number (2054052).

Almost surely, 2^28687218 is an apocalyptic number.

28687218 is an abundant number, since it is smaller than the sum of its proper divisors (37042446).

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

28687218 is a wasteful number, since it uses less digits than its factorization.

28687218 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1666.

The product of its digits is 86016, while the sum is 42.

The square root of 28687218 is about 5356.0449960769. The cubic root of 28687218 is about 306.1231295671.

The spelling of 28687218 in words is "twenty-eight million, six hundred eighty-seven thousand, two hundred eighteen".