2181278729 has 8 divisors (see below), whose sum is σ = 2502091008. Its totient is φ = 1862766720.

The previous prime is 2181278713. The next prime is 2181278731. The reversal of 2181278729 is 9278721812.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 2181278729 - 2⁴ = 2181278713 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2181278929) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 573032 + ... + 576825.

It is an arithmetic number, because the mean of its divisors is an integer number (312761376).

Almost surely, 2^2181278729 is an apocalyptic number.

It is an amenable number.

2181278729 is a deficient number, since it is larger than the sum of its proper divisors (320812279).

2181278729 is a wasteful number, since it uses less digits than its factorization.

2181278729 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1150135.

The product of its digits is 225792, while the sum is 47.

The square root of 2181278729 is about 46704.1617952833. The cubic root of 2181278729 is about 1296.8917317232.

The spelling of 2181278729 in words is "two billion, one hundred eighty-one million, two hundred seventy-eight thousand, seven hundred twenty-nine".