43061981 has 2 divisors, whose sum is σ = 43061982. Its totient is φ = 43061980.

The previous prime is 43061971. The next prime is 43061983. The reversal of 43061981 is 18916034.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 41925625 + 1136356 = 6475^2 + 1066^2 .

It is a cyclic number.

It is not a de Polignac number, because 43061981 - 2¹⁰ = 43060957 is a prime.

It is a super-2 number, since 2×43061981² = 3708668415288722, which contains 22 as substring.

Together with 43061983, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (43061983) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21530990 + 21530991.

It is an arithmetic number, because the mean of its divisors is an integer number (21530991).

Almost surely, 2^43061981 is an apocalyptic number.

It is an amenable number.

43061981 is a deficient number, since it is larger than the sum of its proper divisors (1).

43061981 is an equidigital number, since it uses as much as digits as its factorization.

43061981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5184, while the sum is 32.

The square root of 43061981 is about 6562.1628294336. The cubic root of 43061981 is about 350.5080539974.

The spelling of 43061981 in words is "forty-three million, sixty-one thousand, nine hundred eighty-one".