28715691 has 4 divisors (see below), whose sum is σ = 38287592. Its totient is φ = 19143792.

The previous prime is 28715683. The next prime is 28715699. The reversal of 28715691 is 19651782.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (28715683) and next prime (28715699).

It is not a de Polignac number, because 28715691 - 2³ = 28715683 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28715699) 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, 4785946 + ... + 4785951.

It is an arithmetic number, because the mean of its divisors is an integer number (9571898).

Almost surely, 2^28715691 is an apocalyptic number.

28715691 is a deficient number, since it is larger than the sum of its proper divisors (9571901).

28715691 is an equidigital number, since it uses as much as digits as its factorization.

28715691 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9571900.

The product of its digits is 30240, while the sum is 39.

The square root of 28715691 is about 5358.7023615797. The cubic root of 28715691 is about 306.2243751432.

The spelling of 28715691 in words is "twenty-eight million, seven hundred fifteen thousand, six hundred ninety-one".