43997821 has 8 divisors (see below), whose sum is σ = 50506560. Its totient is φ = 37544928.

The previous prime is 43997813. The next prime is 43997831. The reversal of 43997821 is 12879934.

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 43997821 - 2³ = 43997813 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (43997831) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12256 + ... + 15433.

It is an arithmetic number, because the mean of its divisors is an integer number (6313320).

Almost surely, 2^43997821 is an apocalyptic number.

It is an amenable number.

43997821 is a deficient number, since it is larger than the sum of its proper divisors (6508739).

43997821 is a wasteful number, since it uses less digits than its factorization.

43997821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27923.

The product of its digits is 108864, while the sum is 43.

The square root of 43997821 is about 6633.0853303723. The cubic root of 43997821 is about 353.0290056871.

The spelling of 43997821 in words is "forty-three million, nine hundred ninety-seven thousand, eight hundred twenty-one".