43331555681 has 2 divisors, whose sum is σ = 43331555682. Its totient is φ = 43331555680.

The previous prime is 43331555647. The next prime is 43331555711. The reversal of 43331555681 is 18655513334.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 32472040000 + 10859515681 = 180200^2 + 104209^2 .

It is a cyclic number.

It is not a de Polignac number, because 43331555681 - 2¹⁴ = 43331539297 is a prime.

It is a super-2 number, since 2×43331555681² (a number of 22 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (43331555621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21665777840 + 21665777841.

It is an arithmetic number, because the mean of its divisors is an integer number (21665777841).

Almost surely, 2^43331555681 is an apocalyptic number.

It is an amenable number.

43331555681 is a deficient number, since it is larger than the sum of its proper divisors (1).

43331555681 is an equidigital number, since it uses as much as digits as its factorization.

43331555681 is an evil number, because the sum of its binary digits is even.

The product of its digits is 648000, while the sum is 44.

The spelling of 43331555681 in words is "forty-three billion, three hundred thirty-one million, five hundred fifty-five thousand, six hundred eighty-one".