28356909 has 32 divisors (see below), whose sum is σ = 45686784. Its totient is φ = 15301440.

The previous prime is 28356877. The next prime is 28356929. The reversal of 28356909 is 90965382.

It is not a de Polignac number, because 28356909 - 2⁵ = 28356877 is a prime.

It is a super-2 number, since 2×28356909² = 1608228576068562, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28356929) 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, 27487 + ... + 28499.

It is an arithmetic number, because the mean of its divisors is an integer number (1427712).

Almost surely, 2^28356909 is an apocalyptic number.

It is an amenable number.

28356909 is a deficient number, since it is larger than the sum of its proper divisors (17329875).

28356909 is a wasteful number, since it uses less digits than its factorization.

28356909 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1097.

The product of its (nonzero) digits is 116640, while the sum is 42.

The square root of 28356909 is about 5325.1205620155. The cubic root of 28356909 is about 304.9436749882.

The spelling of 28356909 in words is "twenty-eight million, three hundred fifty-six thousand, nine hundred nine".