28111291 has 12 divisors (see below), whose sum is σ = 30641520. Its totient is φ = 25777440.

The previous prime is 28111271. The next prime is 28111331. The reversal of 28111291 is 19211182.

It is a de Polignac number, because none of the positive numbers 2^k-28111291 is a prime.

It is not an unprimeable number, because it can be changed into a prime (28111201) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 30130 + ... + 31048.

It is an arithmetic number, because the mean of its divisors is an integer number (2553460).

Almost surely, 2^28111291 is an apocalyptic number.

28111291 is a deficient number, since it is larger than the sum of its proper divisors (2530229).

28111291 is a wasteful number, since it uses less digits than its factorization.

28111291 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1126 (or 1113 counting only the distinct ones).

The product of its digits is 288, while the sum is 25.

The square root of 28111291 is about 5302.0082044448. The cubic root of 28111291 is about 304.0606808404.

The spelling of 28111291 in words is "twenty-eight million, one hundred eleven thousand, two hundred ninety-one".