21000020002101 has 24 divisors (see below), whose sum is σ = 34693594079040. Its totient is φ = 11990701832256.

The previous prime is 21000020002099. The next prime is 21000020002133. The reversal of 21000020002101 is 10120002000012.

It is not a de Polignac number, because 21000020002101 - 2¹ = 21000020002099 is a prime.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21000020000101) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 129218115 + ... + 129380528.

It is an arithmetic number, because the mean of its divisors is an integer number (1445566419960).

Almost surely, 2^{21000020002101} is an apocalyptic number.

21000020002101 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21000020002101 is a deficient number, since it is larger than the sum of its proper divisors (13693574076939).

21000020002101 is a wasteful number, since it uses less digits than its factorization.

21000020002101 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 258599945 (or 258599942 counting only the distinct ones).

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

Adding to 21000020002101 its reverse (10120002000012), we get a palindrome (31120022002113).

The spelling of 21000020002101 in words is "twenty-one trillion, twenty million, two thousand, one hundred one".