28696321 has 4 divisors (see below), whose sum is σ = 28959700. Its totient is φ = 28432944.

The previous prime is 28696319. The next prime is 28696331. The reversal of 28696321 is 12369682.

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

It can be written as a sum of positive squares in 2 ways, for example, as 26010000 + 2686321 = 5100^2 + 1639^2 .

It is a cyclic number.

It is not a de Polignac number, because 28696321 - 2¹ = 28696319 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28696331) 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, 131526 + ... + 131743.

It is an arithmetic number, because the mean of its divisors is an integer number (7239925).

Almost surely, 2^28696321 is an apocalyptic number.

It is an amenable number.

28696321 is a deficient number, since it is larger than the sum of its proper divisors (263379).

28696321 is a wasteful number, since it uses less digits than its factorization.

28696321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 263378.

The product of its digits is 31104, while the sum is 37.

The square root of 28696321 is about 5356.8947161579. The cubic root of 28696321 is about 306.1555057070.

The spelling of 28696321 in words is "twenty-eight million, six hundred ninety-six thousand, three hundred twenty-one".