28218100 has 36 divisors (see below), whose sum is σ = 61519500. Its totient is φ = 11234560.

The previous prime is 28218061. The next prime is 28218103. The reversal of 28218100 is 181282.

It can be written as a sum of positive squares in 6 ways, for example, as 781456 + 27436644 = 884^2 + 5238^2 .

It is a super-2 number, since 2×28218100² = 1592522335220000, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28218103) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 26376 + ... + 27424.

It is an arithmetic number, because the mean of its divisors is an integer number (1708875).

Almost surely, 2^28218100 is an apocalyptic number.

28218100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28218100 is an abundant number, since it is smaller than the sum of its proper divisors (33301400).

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

28218100 is a wasteful number, since it uses less digits than its factorization.

28218100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1332 (or 1325 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 22.

The square root of 28218100 is about 5312.0711591619. The cubic root of 28218100 is about 304.4452875384.

Adding to 28218100 its reverse (181282), we get a palindrome (28399382).

The spelling of 28218100 in words is "twenty-eight million, two hundred eighteen thousand, one hundred".