21181820001 has 8 divisors (see below), whose sum is σ = 28286489184. Its totient is φ = 14099182080.

The previous prime is 21181819999. The next prime is 21181820017. The reversal of 21181820001 is 10002818112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21181820001 - 2¹ = 21181819999 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21181820071) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5505571 + ... + 5509416.

It is an arithmetic number, because the mean of its divisors is an integer number (3535811148).

Almost surely, 2^21181820001 is an apocalyptic number.

It is an amenable number.

21181820001 is a deficient number, since it is larger than the sum of its proper divisors (7104669183).

21181820001 is a wasteful number, since it uses less digits than its factorization.

21181820001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11015631.

The product of its (nonzero) digits is 256, while the sum is 24.

The spelling of 21181820001 in words is "twenty-one billion, one hundred eighty-one million, eight hundred twenty thousand, one".