21054905721600 has 432 divisors, whose sum is σ = 70377647104800. Its totient is φ = 5542760284160.

The previous prime is 21054905721589. The next prime is 21054905721611. The reversal of 21054905721600 is 612750945012.

It is an interprime number because it is at equal distance from previous prime (21054905721589) and next prime (21054905721611).

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, 1115836966 + ... + 1115855834.

It is an arithmetic number, because the mean of its divisors is an integer number (162911220150).

Almost surely, 2^{21054905721600} is an apocalyptic number.

21054905721600 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 21054905721600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35188823552400).

21054905721600 is an abundant number, since it is smaller than the sum of its proper divisors (49322741383200).

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

21054905721600 is a wasteful number, since it uses less digits than its factorization.

21054905721600 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19640 (or 19621 counting only the distinct ones).

The product of its (nonzero) digits is 151200, while the sum is 42.

The spelling of 21054905721600 in words is "twenty-one trillion, fifty-four billion, nine hundred five million, seven hundred twenty-one thousand, six hundred".