28577681 has 4 divisors (see below), whose sum is σ = 31175664. Its totient is φ = 25979700.

The previous prime is 28577669. The next prime is 28577693. The reversal of 28577681 is 18677582.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (28577669) and next prime (28577693).

It is a cyclic number.

It is not a de Polignac number, because 28577681 - 2⁶ = 28577617 is a prime.

It is a super-2 number, since 2×28577681² = 1633367702675522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28577621) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1298975 + ... + 1298996.

It is an arithmetic number, because the mean of its divisors is an integer number (7793916).

Almost surely, 2^28577681 is an apocalyptic number.

It is an amenable number.

28577681 is a deficient number, since it is larger than the sum of its proper divisors (2597983).

28577681 is a wasteful number, since it uses less digits than its factorization.

28577681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2597982.

The product of its digits is 188160, while the sum is 44.

The square root of 28577681 is about 5345.8096673937. The cubic root of 28577681 is about 305.7330071740.

Subtracting from 28577681 its reverse (18677582), we obtain a palindrome (9900099).

The spelling of 28577681 in words is "twenty-eight million, five hundred seventy-seven thousand, six hundred eighty-one".