28917081 has 20 divisors (see below), whose sum is σ = 43753600. Its totient is φ = 19029816.

The previous prime is 28917073. The next prime is 28917101. The reversal of 28917081 is 18071982.

It is not a de Polignac number, because 28917081 - 2³ = 28917073 is a prime.

It is a super-2 number, since 2×28917081² = 1672395147121122, 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 (28917041) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 4140 + ... + 8658.

It is an arithmetic number, because the mean of its divisors is an integer number (2187680).

Almost surely, 2^28917081 is an apocalyptic number.

It is an amenable number.

28917081 is a deficient number, since it is larger than the sum of its proper divisors (14836519).

28917081 is an equidigital number, since it uses as much as digits as its factorization.

28917081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4610 (or 4601 counting only the distinct ones).

The product of its (nonzero) digits is 8064, while the sum is 36.

The square root of 28917081 is about 5377.4604601057. The cubic root of 28917081 is about 306.9385829953.

The spelling of 28917081 in words is "twenty-eight million, nine hundred seventeen thousand, eighty-one".