28715251 has 4 divisors (see below), whose sum is σ = 30226600. Its totient is φ = 27203904.

The previous prime is 28715233. The next prime is 28715257. The reversal of 28715251 is 15251782.

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

It is a cyclic number.

It is not a de Polignac number, because 28715251 - 2¹¹ = 28713203 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28715257) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 755646 + ... + 755683.

It is an arithmetic number, because the mean of its divisors is an integer number (7556650).

Almost surely, 2^28715251 is an apocalyptic number.

28715251 is a deficient number, since it is larger than the sum of its proper divisors (1511349).

28715251 is a wasteful number, since it uses less digits than its factorization.

28715251 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1511348.

The product of its digits is 5600, while the sum is 31.

The square root of 28715251 is about 5358.6613067071. The cubic root of 28715251 is about 306.2228110806. Note that the first 3 decimals are identical.

The spelling of 28715251 in words is "twenty-eight million, seven hundred fifteen thousand, two hundred fifty-one".