21208554000 has 720 divisors, whose sum is σ = 82142825856. Its totient is φ = 5287680000.

The previous prime is 21208553987. The next prime is 21208554007. The reversal of 21208554000 is 45580212.

It is a happy number.

21208554000 is a `hidden beast` number, since 2 + 1 + 208 + 55 + 400 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (720).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (21208554007) by changing a digit.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 140453925 + ... + 140454075.

Almost surely, 2^21208554000 is an apocalyptic number.

21208554000 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 21208554000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41071412928).

21208554000 is an abundant number, since it is smaller than the sum of its proper divisors (60934271856).

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

21208554000 is a wasteful number, since it uses less digits than its factorization.

21208554000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 223 (or 178 counting only the distinct ones).

The product of its (nonzero) digits is 3200, while the sum is 27.

It can be divided in two parts, 212085 and 54000, that added together give a triangular number (266085 = T₇₂₉).

The spelling of 21208554000 in words is "twenty-one billion, two hundred eight million, five hundred fifty-four thousand".