28981931 has 8 divisors (see below), whose sum is σ = 32636928. Its totient is φ = 25497000.

The previous prime is 28981907. The next prime is 28981943. The reversal of 28981931 is 13918982.

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 28981931 - 2⁶ = 28981867 is a prime.

It is a super-2 number, since 2×28981931² = 1679904648977522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28981031) 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, 42155 + ... + 42836.

It is an arithmetic number, because the mean of its divisors is an integer number (4079616).

Almost surely, 2^28981931 is an apocalyptic number.

28981931 is a deficient number, since it is larger than the sum of its proper divisors (3654997).

28981931 is a wasteful number, since it uses less digits than its factorization.

28981931 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 85033.

The product of its digits is 31104, while the sum is 41.

The square root of 28981931 is about 5383.4868811951. The cubic root of 28981931 is about 307.1678604693.

The spelling of 28981931 in words is "twenty-eight million, nine hundred eighty-one thousand, nine hundred thirty-one".