21550500505555 has 16 divisors (see below), whose sum is σ = 29555185959360. Its totient is φ = 14777379142272.

The previous prime is 21550500505549. The next prime is 21550500505561. The reversal of 21550500505555 is 55550500505512.

It is an interprime number because it is at equal distance from previous prime (21550500505549) and next prime (21550500505561).

It is a cyclic number.

It is not a de Polignac number, because 21550500505555 - 2¹³ = 21550500497363 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2841537 + ... + 7153693.

It is an arithmetic number, because the mean of its divisors is an integer number (1847199122460).

Almost surely, 2^{21550500505555} is an apocalyptic number.

21550500505555 is a deficient number, since it is larger than the sum of its proper divisors (8004685453805).

21550500505555 is a wasteful number, since it uses less digits than its factorization.

21550500505555 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4454958.

The product of its (nonzero) digits is 781250, while the sum is 43.

Subtracting from 21550500505555 its sum of digits (43), we obtain a palindrome (21550500505512).

The spelling of 21550500505555 in words is "twenty-one trillion, five hundred fifty billion, five hundred million, five hundred five thousand, five hundred fifty-five".