28251971 has 4 divisors (see below), whose sum is σ = 30820344. Its totient is φ = 25683600.

The previous prime is 28251961. The next prime is 28252009. The reversal of 28251971 is 17915282.

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 28251971 - 2⁶ = 28251907 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28251961) 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, 1284170 + ... + 1284191.

It is an arithmetic number, because the mean of its divisors is an integer number (7705086).

Almost surely, 2^28251971 is an apocalyptic number.

28251971 is a deficient number, since it is larger than the sum of its proper divisors (2568373).

28251971 is a wasteful number, since it uses less digits than its factorization.

28251971 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2568372.

The product of its digits is 10080, while the sum is 35.

The square root of 28251971 is about 5315.2583192165. The cubic root of 28251971 is about 304.5670503219.

The spelling of 28251971 in words is "twenty-eight million, two hundred fifty-one thousand, nine hundred seventy-one".