43554605981 has 4 divisors (see below), whose sum is σ = 44731757532. Its totient is φ = 42377454432.

The previous prime is 43554605947. The next prime is 43554605989. The reversal of 43554605981 is 18950645534.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 18950645534 = 2 ⋅9475322767.

It can be written as a sum of positive squares in 2 ways, for example, as 26819302756 + 16735303225 = 163766^2 + 129365^2 .

It is a cyclic number.

It is not a de Polignac number, because 43554605981 - 2⁶ = 43554605917 is a prime.

It is a super-2 number, since 2×43554605981² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (43554605989) 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, 588575720 + ... + 588575793.

It is an arithmetic number, because the mean of its divisors is an integer number (11182939383).

Almost surely, 2^43554605981 is an apocalyptic number.

It is an amenable number.

43554605981 is a deficient number, since it is larger than the sum of its proper divisors (1177151551).

43554605981 is a wasteful number, since it uses less digits than its factorization.

43554605981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1177151550.

The product of its (nonzero) digits is 2592000, while the sum is 50.

The spelling of 43554605981 in words is "forty-three billion, five hundred fifty-four million, six hundred five thousand, nine hundred eighty-one".