21020012000 has 384 divisors, whose sum is σ = 58845346560. Its totient is φ = 7324262400.

The previous prime is 21020011973. The next prime is 21020012059. The reversal of 21020012000 is 21002012.

It is a Harshad number since it is a multiple of its sum of digits (8).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 79923869 + ... + 79924131.

It is an arithmetic number, because the mean of its divisors is an integer number (153243090).

Almost surely, 2^21020012000 is an apocalyptic number.

21020012000 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21020012000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29422673280).

21020012000 is an abundant number, since it is smaller than the sum of its proper divisors (37825334560).

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

21020012000 is a wasteful number, since it uses less digits than its factorization.

21020012000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 383 (or 365 counting only the distinct ones).

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

Adding to 21020012000 its reverse (21002012), we get a palindrome (21041014012).

The spelling of 21020012000 in words is "twenty-one billion, twenty million, twelve thousand".