28940389 has 4 divisors (see below), whose sum is σ = 29161440. Its totient is φ = 28719340.

The previous prime is 28940369. The next prime is 28940393. The reversal of 28940389 is 98304982.

It is a happy number.

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 a cyclic number.

It is not a de Polignac number, because 28940389 - 2⁹ = 28939877 is a prime.

It is a super-2 number, since 2×28940389² = 1675092230942642, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28940309) 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 3 ways as a sum of consecutive naturals, for example, 110329 + ... + 110590.

It is an arithmetic number, because the mean of its divisors is an integer number (7290360).

Almost surely, 2^28940389 is an apocalyptic number.

It is an amenable number.

28940389 is a deficient number, since it is larger than the sum of its proper divisors (221051).

28940389 is a wasteful number, since it uses less digits than its factorization.

28940389 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 221050.

The product of its (nonzero) digits is 124416, while the sum is 43.

The square root of 28940389 is about 5379.6272175681. The cubic root of 28940389 is about 307.0210279605.

The spelling of 28940389 in words is "twenty-eight million, nine hundred forty thousand, three hundred eighty-nine".