43621993 has 2 divisors, whose sum is σ = 43621994. Its totient is φ = 43621992.

The previous prime is 43621943. The next prime is 43621999. The reversal of 43621993 is 39912634.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 23299929 + 20322064 = 4827^2 + 4508^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-43621993 is a prime.

It is not a weakly prime, because it can be changed into another prime (43621999) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21810996 + 21810997.

It is an arithmetic number, because the mean of its divisors is an integer number (21810997).

Almost surely, 2^43621993 is an apocalyptic number.

It is an amenable number.

43621993 is a deficient number, since it is larger than the sum of its proper divisors (1).

43621993 is an equidigital number, since it uses as much as digits as its factorization.

43621993 is an evil number, because the sum of its binary digits is even.

The product of its digits is 34992, while the sum is 37.

The square root of 43621993 is about 6604.6947696317. The cubic root of 43621993 is about 352.0209423878.

The spelling of 43621993 in words is "forty-three million, six hundred twenty-one thousand, nine hundred ninety-three".