21012240121400 has 192 divisors, whose sum is σ = 54625709266560. Its totient is φ = 7452244800000.

The previous prime is 21012240121381. The next prime is 21012240121403. The reversal of 21012240121400 is 412104221012.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21012240121403) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 14181695 + ... + 15593105.

It is an arithmetic number, because the mean of its divisors is an integer number (284508902430).

Almost surely, 2^{21012240121400} is an apocalyptic number.

21012240121400 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 21012240121400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27312854633280).

21012240121400 is an abundant number, since it is smaller than the sum of its proper divisors (33613469145160).

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

21012240121400 is a wasteful number, since it uses less digits than its factorization.

21012240121400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1411606 (or 1411597 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 20.

Adding to 21012240121400 its reverse (412104221012), we get a palindrome (21424344342412).

The spelling of 21012240121400 in words is "twenty-one trillion, twelve billion, two hundred forty million, one hundred twenty-one thousand, four hundred".