28364391 has 32 divisors (see below), whose sum is σ = 46928640. Its totient is φ = 16783200.

The previous prime is 28364387. The next prime is 28364393. The reversal of 28364391 is 19346382.

28364391 is a `hidden beast` number, since 2 + 8 + 3 + 643 + 9 + 1 = 666.

It is not a de Polignac number, because 28364391 - 2² = 28364387 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28364393) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 11661 + ... + 13881.

It is an arithmetic number, because the mean of its divisors is an integer number (1466520).

Almost surely, 2^28364391 is an apocalyptic number.

28364391 is a deficient number, since it is larger than the sum of its proper divisors (18564249).

28364391 is a wasteful number, since it uses less digits than its factorization.

28364391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2284 (or 2278 counting only the distinct ones).

The product of its digits is 31104, while the sum is 36.

The square root of 28364391 is about 5325.8230349872. The cubic root of 28364391 is about 304.9704925319.

Subtracting from 28364391 its reverse (19346382), we obtain a square (9018009 = 3003²).

It can be divided in two parts, 2836 and 4391, that added together give a palindrome (7227).

The spelling of 28364391 in words is "twenty-eight million, three hundred sixty-four thousand, three hundred ninety-one".