2181242471409 has 27 divisors (see below), whose sum is σ = 3162690491233. Its totient is φ = 1448640984192.

The previous prime is 2181242471381. The next prime is 2181242471417. The reversal of 2181242471409 is 9041742421812.

The square root of 2181242471409 is 1476903.

It is a perfect power (a square), and thus also a powerful number.

2181242471409 is a `hidden beast` number, since 2 + 1 + 81 + 2 + 424 + 7 + 140 + 9 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 1559384055009 + 621858416400 = 1248753^2 + 788580^2 .

It is not a de Polignac number, because 2181242471409 - 2²³ = 2181234082801 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2181242476409) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 1404533977 + ... + 1404535529.

Almost surely, 2^{2181242471409} is an apocalyptic number.

2181242471409 is the 1476903-rd square number.

2181242471409 is the 738452-nd centered octagonal number.

It is an amenable number.

2181242471409 is a deficient number, since it is larger than the sum of its proper divisors (981448019824).

2181242471409 is an frugal number, since it uses more digits than its factorization.

2181242471409 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3746 (or 1873 counting only the distinct ones).

The product of its (nonzero) digits is 258048, while the sum is 45.

The spelling of 2181242471409 in words is "two trillion, one hundred eighty-one billion, two hundred forty-two million, four hundred seventy-one thousand, four hundred nine".