28640838 has 32 divisors (see below), whose sum is σ = 60521472. Its totient is φ = 9021600.

The previous prime is 28640831. The next prime is 28640839. The reversal of 28640838 is 83804682.

It is a junction number, because it is equal to n+sod(n) for n = 28640796 and 28640805.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28640831) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6208 + ... + 9788.

It is an arithmetic number, because the mean of its divisors is an integer number (1891296).

Almost surely, 2^28640838 is an apocalyptic number.

28640838 is an abundant number, since it is smaller than the sum of its proper divisors (31880634).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

28640838 is a wasteful number, since it uses less digits than its factorization.

28640838 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3660.

The product of its (nonzero) digits is 73728, while the sum is 39.

The square root of 28640838 is about 5351.7135573571. The cubic root of 28640838 is about 305.9580659355.

The spelling of 28640838 in words is "twenty-eight million, six hundred forty thousand, eight hundred thirty-eight".