28218491 has 16 divisors (see below), whose sum is σ = 32901120. Its totient is φ = 23704800.

The previous prime is 28218469. The next prime is 28218499. The reversal of 28218491 is 19481282.

It is not a de Polignac number, because 28218491 - 2¹⁴ = 28202107 is a prime.

It is not an unprimeable number, because it can be changed into a prime (28218499) 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, 117950 + ... + 118188.

It is an arithmetic number, because the mean of its divisors is an integer number (2056320).

Almost surely, 2^28218491 is an apocalyptic number.

28218491 is a deficient number, since it is larger than the sum of its proper divisors (4682629).

28218491 is a wasteful number, since it uses less digits than its factorization.

28218491 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 514.

The product of its digits is 9216, while the sum is 35.

The square root of 28218491 is about 5312.1079620053. The cubic root of 28218491 is about 304.4466936992.

The spelling of 28218491 in words is "twenty-eight million, two hundred eighteen thousand, four hundred ninety-one".