28158911 has 4 divisors (see below), whose sum is σ = 30718824. Its totient is φ = 25599000.

The previous prime is 28158859. The next prime is 28158917. The reversal of 28158911 is 11985182.

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 28158911 - 2²² = 23964607 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 (28158917) 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, 1279940 + ... + 1279961.

It is an arithmetic number, because the mean of its divisors is an integer number (7679706).

Almost surely, 2^28158911 is an apocalyptic number.

28158911 is a deficient number, since it is larger than the sum of its proper divisors (2559913).

28158911 is a wasteful number, since it uses less digits than its factorization.

28158911 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2559912.

The product of its digits is 5760, while the sum is 35.

The square root of 28158911 is about 5306.4970554972. The cubic root of 28158911 is about 304.2322750156.

The spelling of 28158911 in words is "twenty-eight million, one hundred fifty-eight thousand, nine hundred eleven".