40643999 has 8 divisors (see below), whose sum is σ = 44901120. Its totient is φ = 36480600.

The previous prime is 40643971. The next prime is 40644001. The reversal of 40643999 is 99934604.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-40643999 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (40643969) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 22517 + ... + 24254.

It is an arithmetic number, because the mean of its divisors is an integer number (5612640).

Almost surely, 2^40643999 is an apocalyptic number.

40643999 is a deficient number, since it is larger than the sum of its proper divisors (4257121).

40643999 is a wasteful number, since it uses less digits than its factorization.

40643999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 46861.

The product of its (nonzero) digits is 209952, while the sum is 44.

The square root of 40643999 is about 6375.2646219588. The cubic root of 40643999 is about 343.8207980236.

Subtracting 40643999 from its reverse (99934604), we obtain a triangular number (59290605 = T₁₀₈₈₉).

The spelling of 40643999 in words is "forty million, six hundred forty-three thousand, nine hundred ninety-nine".