28942381 has 16 divisors (see below), whose sum is σ = 33236784. Its totient is φ = 24966144.

The previous prime is 28942379. The next prime is 28942387. The reversal of 28942381 is 18324982.

It can be written as a sum of positive squares in 8 ways, for example, as 1798281 + 27144100 = 1341^2 + 5210^2 .

It is a cyclic number.

It is not a de Polignac number, because 28942381 - 2¹ = 28942379 is a prime.

It is a super-2 number, since 2×28942381² = 1675322835898322, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 28942381.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28942387) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 37855 + ... + 38611.

It is an arithmetic number, because the mean of its divisors is an integer number (2077299).

Almost surely, 2^28942381 is an apocalyptic number.

It is an amenable number.

28942381 is a deficient number, since it is larger than the sum of its proper divisors (4294403).

28942381 is a wasteful number, since it uses less digits than its factorization.

28942381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 960.

The product of its digits is 27648, while the sum is 37.

The square root of 28942381 is about 5379.8123573225. The cubic root of 28942381 is about 307.0280720015.

The spelling of 28942381 in words is "twenty-eight million, nine hundred forty-two thousand, three hundred eighty-one".