43686721 has 8 divisors (see below), whose sum is σ = 47200104. Its totient is φ = 40195200.

The previous prime is 43686707. The next prime is 43686737. The reversal of 43686721 is 12768634.

It can be written as a sum of positive squares in 4 ways, for example, as 640000 + 43046721 = 800^2 + 6561^2 .

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 43686721 - 2²³ = 35298113 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (43686701) 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, 1180 + ... + 9421.

It is an arithmetic number, because the mean of its divisors is an integer number (5900013).

Almost surely, 2^43686721 is an apocalyptic number.

It is an amenable number.

43686721 is a deficient number, since it is larger than the sum of its proper divisors (3513383).

43686721 is a wasteful number, since it uses less digits than its factorization.

43686721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10931.

The product of its digits is 48384, while the sum is 37.

The square root of 43686721 is about 6609.5931039664. The cubic root of 43686721 is about 352.1949704351.

The spelling of 43686721 in words is "forty-three million, six hundred eighty-six thousand, seven hundred twenty-one".