28031306 has 4 divisors (see below), whose sum is σ = 42046962. Its totient is φ = 14015652.

The previous prime is 28031303. The next prime is 28031309. The reversal of 28031306 is 60313082.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (28031303) and next prime (28031309).

It can be written as a sum of positive squares in only one way, i.e., 25090081 + 2941225 = 5009^2 + 1715^2 .

It is not an unprimeable number, because it can be changed into a prime (28031303) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7007825 + ... + 7007828.

Almost surely, 2^28031306 is an apocalyptic number.

28031306 is a deficient number, since it is larger than the sum of its proper divisors (14015656).

28031306 is a wasteful number, since it uses less digits than its factorization.

28031306 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14015655.

The product of its (nonzero) digits is 864, while the sum is 23.

The square root of 28031306 is about 5294.4599346864. The cubic root of 28031306 is about 303.7720258151.

Adding to 28031306 its reverse (60313082), we get a palindrome (88344388).

It can be divided in two parts, 2 and 8031306, that added together give a palindrome (8031308).

The spelling of 28031306 in words is "twenty-eight million, thirty-one thousand, three hundred six".