21555323055550 has 12 divisors (see below), whose sum is σ = 40092900883416. Its totient is φ = 8622129222200.

The previous prime is 21555323055509. The next prime is 21555323055569. The reversal of 21555323055550 is 5555032355512.

It is a self number, because there is not a number n which added to its sum of digits gives 21555323055550.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 215553230506 + ... + 215553230605.

It is an arithmetic number, because the mean of its divisors is an integer number (3341075073618).

Almost surely, 2^{21555323055550} is an apocalyptic number.

21555323055550 is a deficient number, since it is larger than the sum of its proper divisors (18537577827866).

21555323055550 is a wasteful number, since it uses less digits than its factorization.

21555323055550 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 431106461123 (or 431106461118 counting only the distinct ones).

The product of its (nonzero) digits is 2812500, while the sum is 46.

The spelling of 21555323055550 in words is "twenty-one trillion, five hundred fifty-five billion, three hundred twenty-three million, fifty-five thousand, five hundred fifty".