28743991 has 8 divisors (see below), whose sum is σ = 30518640. Its totient is φ = 26978688.

The previous prime is 28743983. The next prime is 28744003. The reversal of 28743991 is 19934782.

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 28743991 - 2³ = 28743983 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28743961) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4620 + ... + 8878.

It is an arithmetic number, because the mean of its divisors is an integer number (3814830).

Almost surely, 2^28743991 is an apocalyptic number.

28743991 is a deficient number, since it is larger than the sum of its proper divisors (1774649).

28743991 is a wasteful number, since it uses less digits than its factorization.

28743991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4673.

The product of its digits is 108864, while the sum is 43.

The square root of 28743991 is about 5361.3422759604. The cubic root of 28743991 is about 306.3249392619.

The spelling of 28743991 in words is "twenty-eight million, seven hundred forty-three thousand, nine hundred ninety-one".