21554934840 has 256 divisors, whose sum is σ = 76007116800. Its totient is φ = 5422298112.

The previous prime is 21554934829. The next prime is 21554934887. The reversal of 21554934840 is 4843945512.

21554934840 is a `hidden beast` number, since 2 + 1 + 554 + 93 + 4 + 8 + 4 + 0 = 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 (13) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1807377 + ... + 1819263.

It is an arithmetic number, because the mean of its divisors is an integer number (296902800).

Almost surely, 2^21554934840 is an apocalyptic number.

21554934840 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 21554934840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38003558400).

21554934840 is an abundant number, since it is smaller than the sum of its proper divisors (54452181960).

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

21554934840 is a wasteful number, since it uses less digits than its factorization.

21554934840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12003 (or 11993 counting only the distinct ones).

The product of its (nonzero) digits is 691200, while the sum is 45.

The spelling of 21554934840 in words is "twenty-one billion, five hundred fifty-four million, nine hundred thirty-four thousand, eight hundred forty".