21012043000 has 256 divisors, whose sum is σ = 56376028800. Its totient is φ = 7265894400.

The previous prime is 21012042991. The next prime is 21012043021. The reversal of 21012043000 is 34021012.

It is a Harshad number since it is a multiple of its sum of digits (13).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 23958562 + ... + 23959438.

Almost surely, 2^21012043000 is an apocalyptic number.

21012043000 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 21012043000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28188014400).

21012043000 is an abundant number, since it is smaller than the sum of its proper divisors (35363985800).

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

21012043000 is a wasteful number, since it uses less digits than its factorization.

21012043000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1027 (or 1013 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 13.

Adding to 21012043000 its reverse (34021012), we get a palindrome (21046064012).

The spelling of 21012043000 in words is "twenty-one billion, twelve million, forty-three thousand".