43631867681 has 2 divisors, whose sum is σ = 43631867682. Its totient is φ = 43631867680.

The previous prime is 43631867621. The next prime is 43631867743. The reversal of 43631867681 is 18676813634.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 38370541456 + 5261326225 = 195884^2 + 72535^2 .

It is a cyclic number.

It is not a de Polignac number, because 43631867681 - 2¹⁴ = 43631851297 is a prime.

It is a super-2 number, since 2×43631867681² (a number of 22 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (43631867621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21815933840 + 21815933841.

It is an arithmetic number, because the mean of its divisors is an integer number (21815933841).

Almost surely, 2^43631867681 is an apocalyptic number.

It is an amenable number.

43631867681 is a deficient number, since it is larger than the sum of its proper divisors (1).

43631867681 is an equidigital number, since it uses as much as digits as its factorization.

43631867681 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3483648, while the sum is 53.

The spelling of 43631867681 in words is "forty-three billion, six hundred thirty-one million, eight hundred sixty-seven thousand, six hundred eighty-one".