21551896800 has 360 divisors, whose sum is σ = 89825407056. Its totient is φ = 4926044160.

The previous prime is 21551896753. The next prime is 21551896837. The reversal of 21551896800 is 869815512.

It is a happy number.

21551896800 is a `hidden beast` number, since 2 + 1 + 551 + 8 + 96 + 8 + 0 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (360).

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 polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 429844 + ... + 477356.

Almost surely, 2^21551896800 is an apocalyptic number.

21551896800 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 21551896800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (44912703528).

21551896800 is an abundant number, since it is smaller than the sum of its proper divisors (68273510256).

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

21551896800 is a wasteful number, since it uses less digits than its factorization.

21551896800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 47552 (or 47530 counting only the distinct ones).

The product of its (nonzero) digits is 172800, while the sum is 45.

The spelling of 21551896800 in words is "twenty-one billion, five hundred fifty-one million, eight hundred ninety-six thousand, eight hundred".