21555227400 has 576 divisors, whose sum is σ = 82074746880. Its totient is φ = 4656960000.

The previous prime is 21555227399. The next prime is 21555227411. The reversal of 21555227400 is 472255512.

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 143 ways as a sum of consecutive naturals, for example, 85877275 + ... + 85877525.

It is an arithmetic number, because the mean of its divisors is an integer number (142490880).

Almost surely, 2^21555227400 is an apocalyptic number.

21555227400 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 21555227400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41037373440).

21555227400 is an abundant number, since it is smaller than the sum of its proper divisors (60519519480).

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

21555227400 is a wasteful number, since it uses less digits than its factorization.

21555227400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 434 (or 418 counting only the distinct ones).

The product of its (nonzero) digits is 28000, while the sum is 33.

The spelling of 21555227400 in words is "twenty-one billion, five hundred fifty-five million, two hundred twenty-seven thousand, four hundred".