28013881 has 8 divisors (see below), whose sum is σ = 32110400. Its totient is φ = 23941008.

The previous prime is 28013879. The next prime is 28013893. The reversal of 28013881 is 18831082.

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

It is not a de Polignac number, because 28013881 - 2¹ = 28013879 is a prime.

It is a super-2 number, since 2×28013881² = 1569555057364322, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (28013851) 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, 3291 + ... + 8176.

It is an arithmetic number, because the mean of its divisors is an integer number (4013800).

Almost surely, 2^28013881 is an apocalyptic number.

It is an amenable number.

28013881 is a deficient number, since it is larger than the sum of its proper divisors (4096519).

28013881 is a wasteful number, since it uses less digits than its factorization.

28013881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11823.

The product of its (nonzero) digits is 3072, while the sum is 31.

The square root of 28013881 is about 5292.8140908216. The cubic root of 28013881 is about 303.7090685304.

It can be divided in two parts, 280 and 13881, that added together give a square (14161 = 119²).

The spelling of 28013881 in words is "twenty-eight million, thirteen thousand, eight hundred eighty-one".