39943921 has 8 divisors (see below), whose sum is σ = 40915784. Its totient is φ = 38983680.

The previous prime is 39943873. The next prime is 39943973. The reversal of 39943921 is 12934993.

It can be written as a sum of positive squares in 4 ways, for example, as 18181696 + 21762225 = 4264^2 + 4665^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 39943921 - 2⁷ = 39943793 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (39943021) 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, 4261 + ... + 9901.

It is an arithmetic number, because the mean of its divisors is an integer number (5114473).

Almost surely, 2^39943921 is an apocalyptic number.

It is an amenable number.

39943921 is a deficient number, since it is larger than the sum of its proper divisors (971863).

39943921 is an equidigital number, since it uses as much as digits as its factorization.

39943921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5811.

The product of its digits is 52488, while the sum is 40.

The square root of 39943921 is about 6320.1203311329. The cubic root of 39943921 is about 341.8352916860.

The spelling of 39943921 in words is "thirty-nine million, nine hundred forty-three thousand, nine hundred twenty-one".