2181749543 has 2 divisors, whose sum is σ = 2181749544. Its totient is φ = 2181749542.

The previous prime is 2181749539. The next prime is 2181749561. The reversal of 2181749543 is 3459471812.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 2181749543 - 2² = 2181749539 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 2181749494 and 2181749503.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2181749503) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1090874771 + 1090874772.

It is an arithmetic number, because the mean of its divisors is an integer number (1090874772).

Almost surely, 2^2181749543 is an apocalyptic number.

2181749543 is a deficient number, since it is larger than the sum of its proper divisors (1).

2181749543 is an equidigital number, since it uses as much as digits as its factorization.

2181749543 is an evil number, because the sum of its binary digits is even.

The product of its digits is 241920, while the sum is 44.

The square root of 2181749543 is about 46709.2019092598. The cubic root of 2181749543 is about 1296.9850333953.

The spelling of 2181749543 in words is "two billion, one hundred eighty-one million, seven hundred forty-nine thousand, five hundred forty-three".