28040661 has 30 divisors (see below), whose sum is σ = 46058166. Its totient is φ = 16988400.

The previous prime is 28040659. The next prime is 28040699. The reversal of 28040661 is 16604082.

It can be written as a sum of positive squares in only one way, i.e., 24502500 + 3538161 = 4950^2 + 1881^2 .

It is not a de Polignac number, because 28040661 - 2¹ = 28040659 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28040261) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 29 ways as a sum of consecutive naturals, for example, 8371 + ... + 11231.

Almost surely, 2^28040661 is an apocalyptic number.

It is an amenable number.

28040661 is a deficient number, since it is larger than the sum of its proper divisors (18017505).

28040661 is a wasteful number, since it uses less digits than its factorization.

28040661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2895 (or 2875 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 27.

The square root of 28040661 is about 5295.3433316453. The cubic root of 28040661 is about 303.8058150747.

The spelling of 28040661 in words is "twenty-eight million, forty thousand, six hundred sixty-one".