1643111541 has 16 divisors (see below), whose sum is σ = 2437830720. Its totient is φ = 1093791600.

The previous prime is 1643111539. The next prime is 1643111563. The reversal of 1643111541 is 1451113461.

1643111541 is a `hidden beast` number, since 1 + 6 + 4 + 3 + 111 + 541 = 666.

It is not a de Polignac number, because 1643111541 - 2¹ = 1643111539 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1643111501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 26110 + ... + 62991.

It is an arithmetic number, because the mean of its divisors is an integer number (152364420).

Almost surely, 2^1643111541 is an apocalyptic number.

It is an amenable number.

1643111541 is a deficient number, since it is larger than the sum of its proper divisors (794719179).

1643111541 is an equidigital number, since it uses as much as digits as its factorization.

1643111541 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 89793 (or 89787 counting only the distinct ones).

The product of its digits is 1440, while the sum is 27.

The square root of 1643111541 is about 40535.3122721412. The cubic root of 1643111541 is about 1180.0190413953.

It can be divided in two parts, 16431 and 11541, that added together give a palindrome (27972).

The spelling of 1643111541 in words is "one billion, six hundred forty-three million, one hundred eleven thousand, five hundred forty-one".