28643919 has 4 divisors (see below), whose sum is σ = 38191896. Its totient is φ = 19095944.

The previous prime is 28643917. The next prime is 28643921. The reversal of 28643919 is 91934682.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (28643917) and next prime (28643921).

It is a cyclic number.

It is not a de Polignac number, because 28643919 - 2¹ = 28643917 is a prime.

It is a super-2 number, since 2×28643919² = 1640948191357122, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28643917) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4773984 + ... + 4773989.

It is an arithmetic number, because the mean of its divisors is an integer number (9547974).

Almost surely, 2^28643919 is an apocalyptic number.

28643919 is a deficient number, since it is larger than the sum of its proper divisors (9547977).

28643919 is an equidigital number, since it uses as much as digits as its factorization.

28643919 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9547976.

The product of its digits is 93312, while the sum is 42.

The square root of 28643919 is about 5352.0014013451. The cubic root of 28643919 is about 305.9690365526.

The spelling of 28643919 in words is "twenty-eight million, six hundred forty-three thousand, nine hundred nineteen".