43985381981 has 4 divisors (see below), whose sum is σ = 44008162464. Its totient is φ = 43962601500.

The previous prime is 43985381969. The next prime is 43985382011. The reversal of 43985381981 is 18918358934.

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 43985381981 - 2¹⁸ = 43985119837 is a prime.

It is a super-2 number, since 2×43985381981² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 43985381981.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (43985381911) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11387345 + ... + 11391206.

It is an arithmetic number, because the mean of its divisors is an integer number (11002040616).

Almost surely, 2^43985381981 is an apocalyptic number.

It is an amenable number.

43985381981 is a deficient number, since it is larger than the sum of its proper divisors (22780483).

43985381981 is a wasteful number, since it uses less digits than its factorization.

43985381981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22780482.

The product of its digits is 7464960, while the sum is 59.

The spelling of 43985381981 in words is "forty-three billion, nine hundred eighty-five million, three hundred eighty-one thousand, nine hundred eighty-one".