28129940 has 12 divisors (see below), whose sum is σ = 59072916. Its totient is φ = 11251968.

The previous prime is 28129939. The next prime is 28129991. The reversal of 28129940 is 4992182.

It can be written as a sum of positive squares in 2 ways, for example, as 7463824 + 20666116 = 2732^2 + 4546^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 28129940.

It is a congruent number.

It is an unprimeable number.

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, 703229 + ... + 703268.

It is an arithmetic number, because the mean of its divisors is an integer number (4922743).

Almost surely, 2^28129940 is an apocalyptic number.

28129940 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28129940 is an abundant number, since it is smaller than the sum of its proper divisors (30942976).

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

28129940 is a wasteful number, since it uses less digits than its factorization.

28129940 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1406506 (or 1406504 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 35.

The square root of 28129940 is about 5303.7665861159. The cubic root of 28129940 is about 304.1279038195.

The spelling of 28129940 in words is "twenty-eight million, one hundred twenty-nine thousand, nine hundred forty".