28391687 has 2 divisors, whose sum is σ = 28391688. Its totient is φ = 28391686.

The previous prime is 28391677. The next prime is 28391707. The reversal of 28391687 is 78619382.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28391687 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28391647) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14195843 + 14195844.

It is an arithmetic number, because the mean of its divisors is an integer number (14195844).

Almost surely, 2^28391687 is an apocalyptic number.

28391687 is a deficient number, since it is larger than the sum of its proper divisors (1).

28391687 is an equidigital number, since it uses as much as digits as its factorization.

28391687 is an evil number, because the sum of its binary digits is even.

The product of its digits is 145152, while the sum is 44.

The square root of 28391687 is about 5328.3850273793. The cubic root of 28391687 is about 305.0682889284.

The spelling of 28391687 in words is "twenty-eight million, three hundred ninety-one thousand, six hundred eighty-seven".