28991716 has 12 divisors (see below), whose sum is σ = 54638332. Its totient is φ = 13380768.

The previous prime is 28991659. The next prime is 28991723. The reversal of 28991716 is 61719982.

It can be written as a sum of positive squares in 2 ways, for example, as 9278116 + 19713600 = 3046^2 + 4440^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 278715 + ... + 278818.

Almost surely, 2^28991716 is an apocalyptic number.

28991716 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is an amenable number.

28991716 is a deficient number, since it is larger than the sum of its proper divisors (25646616).

28991716 is a wasteful number, since it uses less digits than its factorization.

28991716 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 557550 (or 557548 counting only the distinct ones).

The product of its digits is 54432, while the sum is 43.

The square root of 28991716 is about 5384.3956021080. The cubic root of 28991716 is about 307.2024256762.

The spelling of 28991716 in words is "twenty-eight million, nine hundred ninety-one thousand, seven hundred sixteen".