43999999999981 has 2 divisors, whose sum is σ = 43999999999982. Its totient is φ = 43999999999980.

The previous prime is 43999999999937. The next prime is 44000000000009. The reversal of 43999999999981 is 18999999999934.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 39985450794025 + 4014549205956 = 6323405^2 + 2003634^2 .

It is a cyclic number.

It is not a de Polignac number, because 43999999999981 - 2¹³ = 43999999991789 is a prime.

It is a super-2 number, since 2×43999999999981² (a number of 28 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (43999999999931) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21999999999990 + 21999999999991.

It is an arithmetic number, because the mean of its divisors is an integer number (21999999999991).

Almost surely, 2^{43999999999981} is an apocalyptic number.

It is an amenable number.

43999999999981 is a deficient number, since it is larger than the sum of its proper divisors (1).

43999999999981 is an equidigital number, since it uses as much as digits as its factorization.

43999999999981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 334731302496, while the sum is 106.

The spelling of 43999999999981 in words is "forty-three trillion, nine hundred ninety-nine billion, nine hundred ninety-nine million, nine hundred ninety-nine thousand, nine hundred eighty-one".