28915691 has 8 divisors (see below), whose sum is σ = 34990560. Its totient is φ = 23326848.

The previous prime is 28915643. The next prime is 28915693. The reversal of 28915691 is 19651982.

It is a happy number.

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 28915691 - 2¹⁰ = 28914667 is a prime.

It is a super-2 number, since 2×28915691² = 1672234372014962, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28915693) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 121376 + ... + 121613.

It is an arithmetic number, because the mean of its divisors is an integer number (4373820).

Almost surely, 2^28915691 is an apocalyptic number.

28915691 is a deficient number, since it is larger than the sum of its proper divisors (6074869).

28915691 is a wasteful number, since it uses less digits than its factorization.

28915691 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 243013.

The product of its digits is 38880, while the sum is 41.

The square root of 28915691 is about 5377.3312153893. The cubic root of 28915691 is about 306.9336648933.

The spelling of 28915691 in words is "twenty-eight million, nine hundred fifteen thousand, six hundred ninety-one".