28750213 has 4 divisors (see below), whose sum is σ = 30441420. Its totient is φ = 27059008.

The previous prime is 28750201. The next prime is 28750217. The reversal of 28750213 is 31205782.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 31205782 = 2 ⋅15602891.

It can be written as a sum of positive squares in 2 ways, for example, as 11168964 + 17581249 = 3342^2 + 4193^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28750213 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 (28750217) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 845578 + ... + 845611.

It is an arithmetic number, because the mean of its divisors is an integer number (7610355).

Almost surely, 2^28750213 is an apocalyptic number.

It is an amenable number.

28750213 is a deficient number, since it is larger than the sum of its proper divisors (1691207).

28750213 is a wasteful number, since it uses less digits than its factorization.

28750213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1691206.

The product of its (nonzero) digits is 3360, while the sum is 28.

The square root of 28750213 is about 5361.9225096974. The cubic root of 28750213 is about 306.3470403017.

Adding to 28750213 its reverse (31205782), we get a palindrome (59955995).

The spelling of 28750213 in words is "twenty-eight million, seven hundred fifty thousand, two hundred thirteen".