21645142400 has 576 divisors, whose sum is σ = 66153087360. Its totient is φ = 6967296000.

The previous prime is 21645142313. The next prime is 21645142403. The reversal of 21645142400 is 424154612.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21645142403) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 296508764 + ... + 296508836.

It is an arithmetic number, because the mean of its divisors is an integer number (114849110).

Almost surely, 2^21645142400 is an apocalyptic number.

21645142400 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 21645142400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33076543680).

21645142400 is an abundant number, since it is smaller than the sum of its proper divisors (44507944960).

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

21645142400 is a wasteful number, since it uses less digits than its factorization.

21645142400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 203 (or 179 counting only the distinct ones).

The product of its (nonzero) digits is 7680, while the sum is 29.

The spelling of 21645142400 in words is "twenty-one billion, six hundred forty-five million, one hundred forty-two thousand, four hundred".