28011213 has 6 divisors (see below), whose sum is σ = 40460654. Its totient is φ = 18674136.

The previous prime is 28011199. The next prime is 28011227. The reversal of 28011213 is 31211082.

It is an interprime number because it is at equal distance from previous prime (28011199) and next prime (28011227).

It can be written as a sum of positive squares in only one way, i.e., 27910089 + 101124 = 5283^2 + 318^2 .

It is not a de Polignac number, because 28011213 - 2¹² = 28007117 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28011283) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1556170 + ... + 1556187.

Almost surely, 2^28011213 is an apocalyptic number.

It is an amenable number.

28011213 is a deficient number, since it is larger than the sum of its proper divisors (12449441).

28011213 is a wasteful number, since it uses less digits than its factorization.

28011213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3112363 (or 3112360 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 18.

The square root of 28011213 is about 5292.5620449835. The cubic root of 28011213 is about 303.6994266256.

Adding to 28011213 its reverse (31211082), we get a palindrome (59222295).

It can be divided in two parts, 28011 and 213, that added together give a square (28224 = 168²).

The spelling of 28011213 in words is "twenty-eight million, eleven thousand, two hundred thirteen".