21554257766400 has 1152 divisors, whose sum is σ = 82857021811200. Its totient is φ = 5486247936000.

The previous prime is 21554257766389. The next prime is 21554257766429. The reversal of 21554257766400 is 466775245512.

21554257766400 is a `hidden beast` number, since 2 + 1 + 5 + 5 + 4 + 2 + 577 + 6 + 64 + 0 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (1152).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 2710882425 + ... + 2710890375.

It is an arithmetic number, because the mean of its divisors is an integer number (71924498100).

Almost surely, 2^{21554257766400} is an apocalyptic number.

21554257766400 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 21554257766400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41428510905600).

21554257766400 is an abundant number, since it is smaller than the sum of its proper divisors (61302764044800).

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

21554257766400 is a wasteful number, since it uses less digits than its factorization.

21554257766400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8082 (or 8051 counting only the distinct ones).

The product of its (nonzero) digits is 14112000, while the sum is 54.

The spelling of 21554257766400 in words is "twenty-one trillion, five hundred fifty-four billion, two hundred fifty-seven million, seven hundred sixty-six thousand, four hundred".