33728643 has 28 divisors (see below), whose sum is σ = 54475120. Its totient is φ = 20750256.

The previous prime is 33728623. The next prime is 33728659. The reversal of 33728643 is 34682733.

33728643 is a `hidden beast` number, since 3 + 3 + 7 + 2 + 8 + 643 = 666.

It is not a de Polignac number, because 33728643 - 2¹⁶ = 33663107 is a prime.

It is a super-2 number, since 2×33728643² = 2275242717242898, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 33728598 and 33728607.

It is not an unprimeable number, because it can be changed into a prime (33728623) by changing a digit.

It is a polite number, since it can be written in 27 ways as a sum of consecutive naturals, for example, 7698 + ... + 11256.

It is an arithmetic number, because the mean of its divisors is an integer number (1945540).

Almost surely, 2^33728643 is an apocalyptic number.

33728643 is a deficient number, since it is larger than the sum of its proper divisors (20746477).

33728643 is an equidigital number, since it uses as much as digits as its factorization.

33728643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3590 (or 3575 counting only the distinct ones).

The product of its digits is 72576, while the sum is 36.

The square root of 33728643 is about 5807.6366105327. The cubic root of 33728643 is about 323.0970228076.

The spelling of 33728643 in words is "thirty-three million, seven hundred twenty-eight thousand, six hundred forty-three".