28131071 has 4 divisors (see below), whose sum is σ = 28345944. Its totient is φ = 27916200.

The previous prime is 28131041. The next prime is 28131079. The reversal of 28131071 is 17013182.

It is a happy number.

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 28131071 - 2¹⁸ = 27868927 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 (28131079) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 107240 + ... + 107501.

It is an arithmetic number, because the mean of its divisors is an integer number (7086486).

Almost surely, 2^28131071 is an apocalyptic number.

28131071 is a deficient number, since it is larger than the sum of its proper divisors (214873).

28131071 is a wasteful number, since it uses less digits than its factorization.

28131071 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 214872.

The product of its (nonzero) digits is 336, while the sum is 23.

The square root of 28131071 is about 5303.8732073834. The cubic root of 28131071 is about 304.1319797145.

The spelling of 28131071 in words is "twenty-eight million, one hundred thirty-one thousand, seventy-one".