2181647811 has 32 divisors (see below), whose sum is σ = 3510169600. Its totient is φ = 1177403040.

The previous prime is 2181647801. The next prime is 2181647863. The reversal of 2181647811 is 1187461812.

It is not a de Polignac number, because 2181647811 - 2⁶ = 2181647747 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 2181647811.

It is not an unprimeable number, because it can be changed into a prime (2181647801) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 123810 + ... + 140328.

It is an arithmetic number, because the mean of its divisors is an integer number (109692800).

Almost surely, 2^2181647811 is an apocalyptic number.

2181647811 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

2181647811 is a deficient number, since it is larger than the sum of its proper divisors (1328521789).

2181647811 is a wasteful number, since it uses less digits than its factorization.

2181647811 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16879.

The product of its digits is 21504, while the sum is 39.

The square root of 2181647811 is about 46708.1129034347. The cubic root of 2181647811 is about 1296.9648742020.

The spelling of 2181647811 in words is "two billion, one hundred eighty-one million, six hundred forty-seven thousand, eight hundred eleven".