43511209981 has 2 divisors, whose sum is σ = 43511209982. Its totient is φ = 43511209980.

The previous prime is 43511209957. The next prime is 43511209991. The reversal of 43511209981 is 18990211534.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 27858948100 + 15652261881 = 166910^2 + 125109^2 .

It is a cyclic number.

It is not a de Polignac number, because 43511209981 - 2¹⁹ = 43510685693 is a prime.

It is a super-2 number, since 2×43511209981² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (43511209991) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21755604990 + 21755604991.

It is an arithmetic number, because the mean of its divisors is an integer number (21755604991).

Almost surely, 2^43511209981 is an apocalyptic number.

It is an amenable number.

43511209981 is a deficient number, since it is larger than the sum of its proper divisors (1).

43511209981 is an equidigital number, since it uses as much as digits as its factorization.

43511209981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 77760, while the sum is 43.

The spelling of 43511209981 in words is "forty-three billion, five hundred eleven million, two hundred nine thousand, nine hundred eighty-one".