28067781 has 8 divisors (see below), whose sum is σ = 42769984. Its totient is φ = 16038720.

The previous prime is 28067759. The next prime is 28067783. The reversal of 28067781 is 18776082.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 28067781 - 2⁶ = 28067717 is a prime.

It is a super-2 number, since 2×28067781² = 1575600660527922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28067783) 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, 668260 + ... + 668301.

It is an arithmetic number, because the mean of its divisors is an integer number (5346248).

Almost surely, 2^28067781 is an apocalyptic number.

28067781 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

28067781 is a deficient number, since it is larger than the sum of its proper divisors (14702203).

28067781 is a wasteful number, since it uses less digits than its factorization.

28067781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1336571.

The product of its (nonzero) digits is 37632, while the sum is 39.

The square root of 28067781 is about 5297.9034532539. The cubic root of 28067781 is about 303.9037271614.

The spelling of 28067781 in words is "twenty-eight million, sixty-seven thousand, seven hundred eighty-one".