28121408 has 56 divisors (see below), whose sum is σ = 65373504. Its totient is φ = 11750400.

The previous prime is 28121389. The next prime is 28121411. The reversal of 28121408 is 80412182.

It is a tau number, because it is divible by the number of its divisors (56).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 17603 + ... + 19133.

It is an arithmetic number, because the mean of its divisors is an integer number (1167384).

Almost surely, 2^28121408 is an apocalyptic number.

28121408 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

28121408 is the 3062-nd octagonal number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 28121408, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32686752).

28121408 is an abundant number, since it is smaller than the sum of its proper divisors (37252096).

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

28121408 is a wasteful number, since it uses less digits than its factorization.

28121408 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1591 (or 1581 counting only the distinct ones).

The product of its (nonzero) digits is 1024, while the sum is 26.

The square root of 28121408 is about 5302.9621910777. The cubic root of 28121408 is about 304.0971526974.

The spelling of 28121408 in words is "twenty-eight million, one hundred twenty-one thousand, four hundred eight".