21001220011 has 8 divisors (see below), whose sum is σ = 23406932880. Its totient is φ = 18725545728.

The previous prime is 21001220003. The next prime is 21001220033. The reversal of 21001220011 is 11002210012.

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

It is a cyclic number.

It is not a de Polignac number, because 21001220011 - 2³ = 21001220003 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21001220011.

It is not an unprimeable number, because it can be changed into a prime (21001227011) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 32509306 + ... + 32509951.

It is an arithmetic number, because the mean of its divisors is an integer number (2925866610).

Almost surely, 2^21001220011 is an apocalyptic number.

21001220011 is a deficient number, since it is larger than the sum of its proper divisors (2405712869).

21001220011 is a wasteful number, since it uses less digits than its factorization.

21001220011 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 65019293.

The product of its (nonzero) digits is 8, while the sum is 10.

Adding to 21001220011 its reverse (11002210012), we get a palindrome (32003430023).

Subtracting from 21001220011 its reverse (11002210012), we obtain a palindrome (9999009999).

The spelling of 21001220011 in words is "twenty-one billion, one million, two hundred twenty thousand, eleven".