28131157 has 4 divisors (see below), whose sum is σ = 28166656. Its totient is φ = 28095660.

The previous prime is 28131151. The next prime is 28131163. The reversal of 28131157 is 75113182.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (28131151) and next prime (28131163).

It is a cyclic number.

It is not a de Polignac number, because 28131157 - 2¹¹ = 28129109 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 (28131151) 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, 16533 + ... + 18154.

It is an arithmetic number, because the mean of its divisors is an integer number (7041664).

Almost surely, 2^28131157 is an apocalyptic number.

It is an amenable number.

28131157 is a deficient number, since it is larger than the sum of its proper divisors (35499).

28131157 is an equidigital number, since it uses as much as digits as its factorization.

28131157 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35498.

The product of its digits is 1680, while the sum is 28.

The square root of 28131157 is about 5303.8813146600. The cubic root of 28131157 is about 304.1322896367.

The spelling of 28131157 in words is "twenty-eight million, one hundred thirty-one thousand, one hundred fifty-seven".