210000210021 has 24 divisors (see below), whose sum is σ = 346680210240. Its totient is φ = 119995551936.

The previous prime is 210000210019. The next prime is 210000210029. The reversal of 210000210021 is 120012000012.

It is not a de Polignac number, because 210000210021 - 2¹ = 210000210019 is a prime.

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

210000210021 is a modest number, since divided by 210021 gives 2100 as remainder.

It is a junction number, because it is equal to n+sod(n) for n = 210000209985 and 210000210012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (210000210029) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2294881 + ... + 2384633.

It is an arithmetic number, because the mean of its divisors is an integer number (14445008760).

Almost surely, 2^210000210021 is an apocalyptic number.

210000210021 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

210000210021 is a deficient number, since it is larger than the sum of its proper divisors (136680000219).

210000210021 is a wasteful number, since it uses less digits than its factorization.

210000210021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 126905 (or 126902 counting only the distinct ones).

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

Adding to 210000210021 its reverse (120012000012), we get a palindrome (330012210033).

The spelling of 210000210021 in words is "two hundred ten billion, two hundred ten thousand, twenty-one".