21372880721400 has 576 divisors, whose sum is σ = 77616975945600. Its totient is φ = 5239388206080.

The previous prime is 21372880721363. The next prime is 21372880721429. The reversal of 21372880721400 is 412708827312.

21372880721400 is a `hidden beast` number, since 213 + 7 + 2 + 8 + 8 + 0 + 7 + 21 + 400 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

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 143 ways as a sum of consecutive naturals, for example, 12821163367 + ... + 12821165033.

It is an arithmetic number, because the mean of its divisors is an integer number (134751694350).

Almost surely, 2^{21372880721400} is an apocalyptic number.

21372880721400 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 21372880721400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38808487972800).

21372880721400 is an abundant number, since it is smaller than the sum of its proper divisors (56244095224200).

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

21372880721400 is a wasteful number, since it uses less digits than its factorization.

21372880721400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3628 (or 3616 counting only the distinct ones).

The product of its (nonzero) digits is 301056, while the sum is 45.

The spelling of 21372880721400 in words is "twenty-one trillion, three hundred seventy-two billion, eight hundred eighty million, seven hundred twenty-one thousand, four hundred".