28778384 has 10 divisors (see below), whose sum is σ = 55758150. Its totient is φ = 14389184.

The previous prime is 28778381. The next prime is 28778389. The reversal of 28778384 is 48387782.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 23814400 + 4963984 = 4880^2 + 2228^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28778381) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 899309 + ... + 899340.

It is an arithmetic number, because the mean of its divisors is an integer number (5575815).

Almost surely, 2^28778384 is an apocalyptic number.

It is an amenable number.

28778384 is a deficient number, since it is larger than the sum of its proper divisors (26979766).

28778384 is a wasteful number, since it uses less digits than its factorization.

28778384 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1798657 (or 1798651 counting only the distinct ones).

The product of its digits is 602112, while the sum is 47.

The square root of 28778384 is about 5364.5488160702. The cubic root of 28778384 is about 306.4470660564.

The spelling of 28778384 in words is "twenty-eight million, seven hundred seventy-eight thousand, three hundred eighty-four".