28742209 has 8 divisors (see below), whose sum is σ = 29077920. Its totient is φ = 28408800.

The previous prime is 28742201. The next prime is 28742213. The reversal of 28742209 is 90224782.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 28742209 - 2³ = 28742201 is a prime.

It is a super-2 number, since 2×28742209² = 1652229156399362, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28742201) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 37389 + ... + 38149.

It is an arithmetic number, because the mean of its divisors is an integer number (3634740).

Almost surely, 2^28742209 is an apocalyptic number.

It is an amenable number.

28742209 is a deficient number, since it is larger than the sum of its proper divisors (335711).

28742209 is a wasteful number, since it uses less digits than its factorization.

28742209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1151.

The product of its (nonzero) digits is 16128, while the sum is 34.

The square root of 28742209 is about 5361.1760836593. The cubic root of 28742209 is about 306.3186088684.

The spelling of 28742209 in words is "twenty-eight million, seven hundred forty-two thousand, two hundred nine".