2181477281 has 4 divisors (see below), whose sum is σ = 2309799492. Its totient is φ = 2053155072.

The previous prime is 2181477253. The next prime is 2181477307. The reversal of 2181477281 is 1827741812.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1075249681 + 1106227600 = 32791^2 + 33260^2 .

It is a cyclic number.

It is not a de Polignac number, because 2181477281 - 2¹⁸ = 2181215137 is a prime.

It is a super-2 number, since 2×2181477281² = 9517686255038305922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2181477211) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 64161080 + ... + 64161113.

It is an arithmetic number, because the mean of its divisors is an integer number (577449873).

Almost surely, 2^2181477281 is an apocalyptic number.

It is an amenable number.

2181477281 is a deficient number, since it is larger than the sum of its proper divisors (128322211).

2181477281 is a wasteful number, since it uses less digits than its factorization.

2181477281 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 128322210.

The product of its digits is 50176, while the sum is 41.

The square root of 2181477281 is about 46706.2873818932. The cubic root of 2181477281 is about 1296.9310806046.

The spelling of 2181477281 in words is "two billion, one hundred eighty-one million, four hundred seventy-seven thousand, two hundred eighty-one".