28955781 has 12 divisors (see below), whose sum is σ = 43643808. Its totient is φ = 18464424.

The previous prime is 28955737. The next prime is 28955819. The reversal of 28955781 is 18755982.

It is a happy number.

It is not a de Polignac number, because 28955781 - 2¹¹ = 28953733 is a prime.

It is a super-2 number, since 2×28955781² = 1676874506639922, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28955701) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 69735 + ... + 70148.

It is an arithmetic number, because the mean of its divisors is an integer number (3636984).

Almost surely, 2^28955781 is an apocalyptic number.

It is an amenable number.

28955781 is a deficient number, since it is larger than the sum of its proper divisors (14688027).

28955781 is a wasteful number, since it uses less digits than its factorization.

28955781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 139912 (or 139909 counting only the distinct ones).

The product of its digits is 201600, while the sum is 45.

The square root of 28955781 is about 5381.0576098013. The cubic root of 28955781 is about 307.0754482164.

The spelling of 28955781 in words is "twenty-eight million, nine hundred fifty-five thousand, seven hundred eighty-one".