2181409937281 has 4 divisors (see below), whose sum is σ = 2181710704212. Its totient is φ = 2181109170352.

The previous prime is 2181409937263. The next prime is 2181409937293. The reversal of 2181409937281 is 1827399041812.

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 1852209399681 + 329200537600 = 1360959^2 + 573760^2 .

It is a cyclic number.

It is not a de Polignac number, because 2181409937281 - 2¹³ = 2181409929089 is a prime.

It is a super-2 number, since 2×2181409937281² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2181409937381) 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, 150372586 + ... + 150387091.

It is an arithmetic number, because the mean of its divisors is an integer number (545427676053).

Almost surely, 2^{2181409937281} is an apocalyptic number.

It is an amenable number.

2181409937281 is a deficient number, since it is larger than the sum of its proper divisors (300766931).

2181409937281 is an equidigital number, since it uses as much as digits as its factorization.

2181409937281 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 300766930.

The product of its (nonzero) digits is 1741824, while the sum is 55.

The spelling of 2181409937281 in words is "two trillion, one hundred eighty-one billion, four hundred nine million, nine hundred thirty-seven thousand, two hundred eighty-one".