21000021020010 has 24 divisors (see below), whose sum is σ = 54600054652260. Its totient is φ = 5600005605312.

The previous prime is 21000021019987. The next prime is 21000021020029. The reversal of 21000021020010 is 1002012000012.

It can be written as a sum of positive squares in 2 ways, for example, as 18678240479889 + 2321780540121 = 4321833^2 + 1523739^2 .

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

It is a junction number, because it is equal to n+sod(n) for n = 21000021019974 and 21000021020001.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 116666783355 + ... + 116666783534.

Almost surely, 2^{21000021020010} is an apocalyptic number.

21000021020010 is an abundant number, since it is smaller than the sum of its proper divisors (33600033632250).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21000021020010 is a wasteful number, since it uses less digits than its factorization.

21000021020010 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 233333566902 (or 233333566899 counting only the distinct ones).

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

Adding to 21000021020010 its reverse (1002012000012), we get a palindrome (22002033020022).

The spelling of 21000021020010 in words is "twenty-one trillion, twenty-one million, twenty thousand, ten".