28909913 has 8 divisors (see below), whose sum is σ = 30180360. Its totient is φ = 27665280.

The previous prime is 28909891. The next prime is 28909921. The reversal of 28909913 is 31990982.

It can be written as a sum of positive squares in 4 ways, for example, as 1420864 + 27489049 = 1192^2 + 5243^2 .

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 28909913 - 2¹⁶ = 28844377 is a prime.

It is not an unprimeable number, because it can be changed into a prime (28909973) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4148 + ... + 8661.

It is an arithmetic number, because the mean of its divisors is an integer number (3772545).

Almost surely, 2^28909913 is an apocalyptic number.

It is an amenable number.

28909913 is a deficient number, since it is larger than the sum of its proper divisors (1270447).

28909913 is a wasteful number, since it uses less digits than its factorization.

28909913 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12907.

The product of its (nonzero) digits is 34992, while the sum is 41.

The square root of 28909913 is about 5376.7939331910. The cubic root of 28909913 is about 306.9132194673.

The spelling of 28909913 in words is "twenty-eight million, nine hundred nine thousand, nine hundred thirteen".