28181197 has 4 divisors (see below), whose sum is σ = 30743136. Its totient is φ = 25619260.

The previous prime is 28181177. The next prime is 28181203. The reversal of 28181197 is 79118182.

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 a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28181197 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 (28181147) 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, 1280953 + ... + 1280974.

It is an arithmetic number, because the mean of its divisors is an integer number (7685784).

Almost surely, 2^28181197 is an apocalyptic number.

It is an amenable number.

28181197 is a deficient number, since it is larger than the sum of its proper divisors (2561939).

28181197 is a wasteful number, since it uses less digits than its factorization.

28181197 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2561938.

The product of its digits is 8064, while the sum is 37.

The square root of 28181197 is about 5308.5965188551. The cubic root of 28181197 is about 304.3125140631.

The spelling of 28181197 in words is "twenty-eight million, one hundred eighty-one thousand, one hundred ninety-seven".