2181816001 has 4 divisors (see below), whose sum is σ = 2232555952. Its totient is φ = 2131076052.

The previous prime is 2181815981. The next prime is 2181816017. The reversal of 2181816001 is 1006181812.

2181816001 is nontrivially palindromic in base 6.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 2181816001 - 2¹³ = 2181807809 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2181816031) 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, 25369911 + ... + 25369996.

It is an arithmetic number, because the mean of its divisors is an integer number (558138988).

Almost surely, 2^2181816001 is an apocalyptic number.

It is an amenable number.

2181816001 is a deficient number, since it is larger than the sum of its proper divisors (50739951).

2181816001 is an equidigital number, since it uses as much as digits as its factorization.

2181816001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50739950.

The product of its (nonzero) digits is 768, while the sum is 28.

The square root of 2181816001 is about 46709.9133054216. The cubic root of 2181816001 is about 1296.9982023612.

Adding to 2181816001 its reverse (1006181812), we get a palindrome (3187997813).

The spelling of 2181816001 in words is "two billion, one hundred eighty-one million, eight hundred sixteen thousand, one".