21540110400 has 378 divisors, whose sum is σ = 78477362730. Its totient is φ = 5603512320.

The previous prime is 21540110369. The next prime is 21540110407. The reversal of 21540110400 is 401104512.

21540110400 is a `hidden beast` number, since 2 + 154 + 0 + 110 + 400 = 666.

It can be written as a sum of positive squares in 3 ways, for example, as 4362338304 + 17177772096 = 66048^2 + 131064^2 .

It is a Harshad number since it is a multiple of its sum of digits (18).

It is not an unprimeable number, because it can be changed into a prime (21540110407) by changing a digit.

It is a polite number, since it can be written in 53 ways as a sum of consecutive naturals, for example, 26625196 + ... + 26626004.

Almost surely, 2^21540110400 is an apocalyptic number.

21540110400 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 21540110400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39238681365).

21540110400 is an abundant number, since it is smaller than the sum of its proper divisors (56937252330).

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

21540110400 is a wasteful number, since it uses less digits than its factorization.

21540110400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 923 (or 862 counting only the distinct ones).

The product of its (nonzero) digits is 160, while the sum is 18.

Adding to 21540110400 its reverse (401104512), we get a palindrome (21941214912).

The spelling of 21540110400 in words is "twenty-one billion, five hundred forty million, one hundred ten thousand, four hundred".