28780691 has 8 divisors (see below), whose sum is σ = 29106000. Its totient is φ = 28457440.

The previous prime is 28780681. The next prime is 28780693. The reversal of 28780691 is 19608782.

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 28780691 - 2¹⁸ = 28518547 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28780693) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 62201 + ... + 62661.

It is an arithmetic number, because the mean of its divisors is an integer number (3638250).

Almost surely, 2^28780691 is an apocalyptic number.

28780691 is a deficient number, since it is larger than the sum of its proper divisors (325309).

28780691 is a wasteful number, since it uses less digits than its factorization.

28780691 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1029.

The product of its (nonzero) digits is 48384, while the sum is 41.

The square root of 28780691 is about 5364.7638345038. The cubic root of 28780691 is about 306.4552545459.

The spelling of 28780691 in words is "twenty-eight million, seven hundred eighty thousand, six hundred ninety-one".