21000102000021 has 12 divisors (see below), whose sum is σ = 30343070806048. Its totient is φ = 13995641781864.

The previous prime is 21000102000013. The next prime is 21000102000049. The reversal of 21000102000021 is 12000020100012.

It is not a de Polignac number, because 21000102000021 - 2³ = 21000102000013 is a prime.

It is a super-2 number, since 2×21000102000021² (a number of 27 digits) contains 22 as substring.

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

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21000101999967 and 21000102000012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21000102000121) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 368821465 + ... + 368878398.

Almost surely, 2^{21000102000021} is an apocalyptic number.

It is an amenable number.

21000102000021 is a deficient number, since it is larger than the sum of its proper divisors (9342968806027).

21000102000021 is a wasteful number, since it uses less digits than its factorization.

21000102000021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 737703032 (or 737703029 counting only the distinct ones).

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

Adding to 21000102000021 its reverse (12000020100012), we get a palindrome (33000122100033).

The spelling of 21000102000021 in words is "twenty-one trillion, one hundred two million, twenty-one", and thus it is an aban number.