40128643 has 2 divisors, whose sum is σ = 40128644. Its totient is φ = 40128642.

The previous prime is 40128631. The next prime is 40128659. The reversal of 40128643 is 34682104.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 40128643 - 2⁹ = 40128131 is a prime.

It is a super-2 number, since 2×40128643² = 3220615978042898, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (40128623) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20064321 + 20064322.

It is an arithmetic number, because the mean of its divisors is an integer number (20064322).

Almost surely, 2^40128643 is an apocalyptic number.

40128643 is a deficient number, since it is larger than the sum of its proper divisors (1).

40128643 is an equidigital number, since it uses as much as digits as its factorization.

40128643 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4608, while the sum is 28.

The square root of 40128643 is about 6334.7172786163. The cubic root of 40128643 is about 342.3614243952.

The spelling of 40128643 in words is "forty million, one hundred twenty-eight thousand, six hundred forty-three".