21001000220001 has 64 divisors (see below), whose sum is σ = 33562267200000. Its totient is φ = 12945442498560.

The previous prime is 21001000219993. The next prime is 21001000220009. The reversal of 21001000220001 is 10002200010012.

It is an interprime number because it is at equal distance from previous prime (21001000219993) and next prime (21001000220009).

It is not a de Polignac number, because 21001000220001 - 2³ = 21001000219993 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is not an unprimeable number, because it can be changed into a prime (21001000220009) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1008376 + ... + 6558873.

It is an arithmetic number, because the mean of its divisors is an integer number (524410425000).

Almost surely, 2^{21001000220001} is an apocalyptic number.

It is an amenable number.

21001000220001 is a deficient number, since it is larger than the sum of its proper divisors (12561266979999).

21001000220001 is a wasteful number, since it uses less digits than its factorization.

21001000220001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7567431 (or 7567425 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

Adding to 21001000220001 its reverse (10002200010012), we get a palindrome (31003200230013).

The spelling of 21001000220001 in words is "twenty-one trillion, one billion, two hundred twenty thousand, one".