28973909 has 4 divisors (see below), whose sum is σ = 28991340. Its totient is φ = 28956480.

The previous prime is 28973869. The next prime is 28973927. The reversal of 28973909 is 90937982.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 90937982 = 2 ⋅45468991.

It can be written as a sum of positive squares in 2 ways, for example, as 3319684 + 25654225 = 1822^2 + 5065^2 .

It is a cyclic number.

It is not a de Polignac number, because 28973909 - 2²⁰ = 27925333 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 (28973939) 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, 5924 + ... + 9645.

It is an arithmetic number, because the mean of its divisors is an integer number (7247835).

Almost surely, 2^28973909 is an apocalyptic number.

It is an amenable number.

28973909 is a deficient number, since it is larger than the sum of its proper divisors (17431).

28973909 is a wasteful number, since it uses less digits than its factorization.

28973909 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17430.

The product of its (nonzero) digits is 244944, while the sum is 47.

The square root of 28973909 is about 5382.7417734831. The cubic root of 28973909 is about 307.1395172008.

The spelling of 28973909 in words is "twenty-eight million, nine hundred seventy-three thousand, nine hundred nine".