28031213 has 8 divisors (see below), whose sum is σ = 33721920. Its totient is φ = 22762080.

The previous prime is 28031191. The next prime is 28031239. The reversal of 28031213 is 31213082.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 28031213 - 2⁶ = 28031149 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 (28031243) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 105248 + ... + 105513.

It is an arithmetic number, because the mean of its divisors is an integer number (4215240).

Almost surely, 2^28031213 is an apocalyptic number.

It is an amenable number.

28031213 is a deficient number, since it is larger than the sum of its proper divisors (5690707).

28031213 is a wasteful number, since it uses less digits than its factorization.

28031213 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 210787.

The product of its (nonzero) digits is 288, while the sum is 20.

The square root of 28031213 is about 5294.4511519137. The cubic root of 28031213 is about 303.7716898713.

Adding to 28031213 its reverse (31213082), we get a palindrome (59244295).

The spelling of 28031213 in words is "twenty-eight million, thirty-one thousand, two hundred thirteen".