28881681 has 16 divisors (see below), whose sum is σ = 39610560. Its totient is φ = 18708480.

The previous prime is 28881679. The next prime is 28881703. The reversal of 28881681 is 18618882.

It is not a de Polignac number, because 28881681 - 2¹ = 28881679 is a prime.

It is a super-2 number, since 2×28881681² = 1668302994771522, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (28886681) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 30625 + ... + 31553.

It is an arithmetic number, because the mean of its divisors is an integer number (2475660).

Almost surely, 2^28881681 is an apocalyptic number.

It is an amenable number.

28881681 is a deficient number, since it is larger than the sum of its proper divisors (10728879).

28881681 is a wasteful number, since it uses less digits than its factorization.

28881681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1216.

The product of its digits is 49152, while the sum is 42.

The square root of 28881681 is about 5374.1679355971. The cubic root of 28881681 is about 306.8132814740.

The spelling of 28881681 in words is "twenty-eight million, eight hundred eighty-one thousand, six hundred eighty-one".