28165381 has 2 divisors, whose sum is σ = 28165382. Its totient is φ = 28165380.

The previous prime is 28165373. The next prime is 28165411. The reversal of 28165381 is 18356182.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20848356 + 7317025 = 4566^2 + 2705^2 .

It is a cyclic number.

It is not a de Polignac number, because 28165381 - 2³ = 28165373 is a prime.

It is a super-2 number, since 2×28165381² = 1586577373750322, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28165981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14082690 + 14082691.

It is an arithmetic number, because the mean of its divisors is an integer number (14082691).

Almost surely, 2^28165381 is an apocalyptic number.

It is an amenable number.

28165381 is a deficient number, since it is larger than the sum of its proper divisors (1).

28165381 is an equidigital number, since it uses as much as digits as its factorization.

28165381 is an evil number, because the sum of its binary digits is even.

The product of its digits is 11520, while the sum is 34.

The square root of 28165381 is about 5307.1066505206. The cubic root of 28165381 is about 304.2555741184.

The spelling of 28165381 in words is "twenty-eight million, one hundred sixty-five thousand, three hundred eighty-one".