28646381 has 2 divisors, whose sum is σ = 28646382. Its totient is φ = 28646380.

The previous prime is 28646369. The next prime is 28646383. The reversal of 28646381 is 18364682.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 27510025 + 1136356 = 5245^2 + 1066^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28646381 is a prime.

It is a super-2 number, since 2×28646381² = 1641230288794322, which contains 22 as substring.

Together with 28646383, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28646383) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14323190 + 14323191.

It is an arithmetic number, because the mean of its divisors is an integer number (14323191).

Almost surely, 2^28646381 is an apocalyptic number.

It is an amenable number.

28646381 is a deficient number, since it is larger than the sum of its proper divisors (1).

28646381 is an equidigital number, since it uses as much as digits as its factorization.

28646381 is an evil number, because the sum of its binary digits is even.

The product of its digits is 55296, while the sum is 38.

The square root of 28646381 is about 5352.2314038165. The cubic root of 28646381 is about 305.9778025107.

The spelling of 28646381 in words is "twenty-eight million, six hundred forty-six thousand, three hundred eighty-one".