28198381 has 2 divisors, whose sum is σ = 28198382. Its totient is φ = 28198380.

The previous prime is 28198369. The next prime is 28198421. The reversal of 28198381 is 18389182.

It is an a-pointer prime, because the next prime (28198421) can be obtained adding 28198381 to its sum of digits (40).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 25918281 + 2280100 = 5091^2 + 1510^2 .

It is a cyclic number.

It is not a de Polignac number, because 28198381 - 2¹⁷ = 28067309 is a prime.

It is a super-2 number, since 2×28198381² = 1590297382042322, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28198301) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14099190 + 14099191.

It is an arithmetic number, because the mean of its divisors is an integer number (14099191).

Almost surely, 2^28198381 is an apocalyptic number.

It is an amenable number.

28198381 is a deficient number, since it is larger than the sum of its proper divisors (1).

28198381 is an equidigital number, since it uses as much as digits as its factorization.

28198381 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 27648, while the sum is 40.

The square root of 28198381 is about 5310.2147790838. The cubic root of 28198381 is about 304.3743548679.

The spelling of 28198381 in words is "twenty-eight million, one hundred ninety-eight thousand, three hundred eighty-one".