21123404501200 has 120 divisors (see below), whose sum is σ = 52393268560640. Its totient is φ = 8175673958400.

The previous prime is 21123404501159. The next prime is 21123404501233. The reversal of 21123404501200 is 210540432112.

It is a Harshad number since it is a multiple of its sum of digits (25).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 92749867 + ... + 92977333.

Almost surely, 2^{21123404501200} is an apocalyptic number.

21123404501200 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 21123404501200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26196634280320).

21123404501200 is an abundant number, since it is smaller than the sum of its proper divisors (31269864059440).

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

21123404501200 is a wasteful number, since it uses less digits than its factorization.

21123404501200 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 235005 (or 234994 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 25.

Adding to 21123404501200 its reverse (210540432112), we get a palindrome (21333944933312).

The spelling of 21123404501200 in words is "twenty-one trillion, one hundred twenty-three billion, four hundred four million, five hundred one thousand, two hundred".