43645981 has 2 divisors, whose sum is σ = 43645982. Its totient is φ = 43645980.

The previous prime is 43645969. The next prime is 43645993. The reversal of 43645981 is 18954634.

It is a balanced prime because it is at equal distance from previous prime (43645969) and next prime (43645993).

It can be written as a sum of positive squares in only one way, i.e., 42133081 + 1512900 = 6491^2 + 1230^2 .

It is a cyclic number.

It is not a de Polignac number, because 43645981 - 2⁵ = 43645949 is a prime.

It is a super-2 number, since 2×43645981² = 3809943314904722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (43648981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21822990 + 21822991.

It is an arithmetic number, because the mean of its divisors is an integer number (21822991).

Almost surely, 2^43645981 is an apocalyptic number.

It is an amenable number.

43645981 is a deficient number, since it is larger than the sum of its proper divisors (1).

43645981 is an equidigital number, since it uses as much as digits as its factorization.

43645981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 103680, while the sum is 40.

The square root of 43645981 is about 6606.5105010134. The cubic root of 43645981 is about 352.0854567180.

The spelling of 43645981 in words is "forty-three million, six hundred forty-five thousand, nine hundred eighty-one".