43873643521 has 2 divisors, whose sum is σ = 43873643522. Its totient is φ = 43873643520.

The previous prime is 43873643507. The next prime is 43873643531. The reversal of 43873643521 is 12534637834.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 43476837121 + 396806400 = 208511^2 + 19920^2 .

It is a cyclic number.

It is not a de Polignac number, because 43873643521 - 2²⁵ = 43840089089 is a prime.

It is not a weakly prime, because it can be changed into another prime (43873643531) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21936821760 + 21936821761.

It is an arithmetic number, because the mean of its divisors is an integer number (21936821761).

Almost surely, 2^43873643521 is an apocalyptic number.

It is an amenable number.

43873643521 is a deficient number, since it is larger than the sum of its proper divisors (1).

43873643521 is an equidigital number, since it uses as much as digits as its factorization.

43873643521 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1451520, while the sum is 46.

The spelling of 43873643521 in words is "forty-three billion, eight hundred seventy-three million, six hundred forty-three thousand, five hundred twenty-one".