43351981 has 4 divisors (see below), whose sum is σ = 44750464. Its totient is φ = 41953500.

The previous prime is 43351937. The next prime is 43352021. The reversal of 43351981 is 18915334.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 43351981 - 2¹³ = 43343789 is a prime.

It is a super-2 number, since 2×43351981² = 3758788513248722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (43358981) 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 3 ways as a sum of consecutive naturals, for example, 699195 + ... + 699256.

It is an arithmetic number, because the mean of its divisors is an integer number (11187616).

Almost surely, 2^43351981 is an apocalyptic number.

It is an amenable number.

43351981 is a deficient number, since it is larger than the sum of its proper divisors (1398483).

43351981 is a wasteful number, since it uses less digits than its factorization.

43351981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1398482.

The product of its digits is 12960, while the sum is 34.

The square root of 43351981 is about 6584.2221256577. Note that the first 3 decimals coincide. The cubic root of 43351981 is about 351.2931239717.

The spelling of 43351981 in words is "forty-three million, three hundred fifty-one thousand, nine hundred eighty-one".