21402116400 has 240 divisors, whose sum is σ = 81759481344. Its totient is φ = 4679178240.

The previous prime is 21402116371. The next prime is 21402116447. The reversal of 21402116400 is 461120412.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (240).

It is a Harshad number since it is a multiple of its sum of digits (21).

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 47 ways as a sum of consecutive naturals, for example, 137812 + ... + 248588.

Almost surely, 2^21402116400 is an apocalyptic number.

21402116400 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 21402116400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40879740672).

21402116400 is an abundant number, since it is smaller than the sum of its proper divisors (60357364944).

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

21402116400 is a wasteful number, since it uses less digits than its factorization.

21402116400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 110828 (or 110817 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 21.

Adding to 21402116400 its reverse (461120412), we get a palindrome (21863236812).

The spelling of 21402116400 in words is "twenty-one billion, four hundred two million, one hundred sixteen thousand, four hundred".