21210021000 has 192 divisors, whose sum is σ = 81931524480. Its totient is φ = 4847990400.

The previous prime is 21210020977. The next prime is 21210021011. The reversal of 21210021000 is 12001212.

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

It is a super Niven number, because it is divisible the sum of any subset of its (nonzero) digits.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 105334 + ... + 231333.

It is an arithmetic number, because the mean of its divisors is an integer number (426726690).

Almost surely, 2^21210021000 is an apocalyptic number.

21210021000 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21210021000 is an abundant number, since it is smaller than the sum of its proper divisors (60721503480).

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

21210021000 is a wasteful number, since it uses less digits than its factorization.

21210021000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 336701 (or 336684 counting only the distinct ones).

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

Adding to 21210021000 its reverse (12001212), we get a palindrome (21222022212).

The spelling of 21210021000 in words is "twenty-one billion, two hundred ten million, twenty-one thousand".