28628891 has 2 divisors, whose sum is σ = 28628892. Its totient is φ = 28628890.

The previous prime is 28628843. The next prime is 28628909. The reversal of 28628891 is 19882682.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 28628891 - 2⁶ = 28628827 is a prime.

It is a super-2 number, since 2×28628891² = 1639226799779762, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (28628591) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14314445 + 14314446.

It is an arithmetic number, because the mean of its divisors is an integer number (14314446).

Almost surely, 2^28628891 is an apocalyptic number.

28628891 is a deficient number, since it is larger than the sum of its proper divisors (1).

28628891 is an equidigital number, since it uses as much as digits as its factorization.

28628891 is an evil number, because the sum of its binary digits is even.

The product of its digits is 110592, while the sum is 44.

The square root of 28628891 is about 5350.5972563818. The cubic root of 28628891 is about 305.9155184214.

The spelling of 28628891 in words is "twenty-eight million, six hundred twenty-eight thousand, eight hundred ninety-one".