21555551301225 has 24 divisors (see below), whose sum is σ = 35640214475520. Its totient is φ = 11495744675520.

The previous prime is 21555551301169. The next prime is 21555551301241. The reversal of 21555551301225 is 52210315555512.

It is not a de Polignac number, because 21555551301225 - 2⁶ = 21555551301161 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 5284494 + ... + 8428343.

It is an arithmetic number, because the mean of its divisors is an integer number (1485008936480).

Almost surely, 2^{21555551301225} is an apocalyptic number.

21555551301225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21555551301225 is a deficient number, since it is larger than the sum of its proper divisors (14084663174295).

21555551301225 is a wasteful number, since it uses less digits than its factorization.

21555551301225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13733809 (or 13733804 counting only the distinct ones).

The product of its (nonzero) digits is 375000, while the sum is 42.

Adding to 21555551301225 its reverse (52210315555512), we get a palindrome (73765866856737).

The spelling of 21555551301225 in words is "twenty-one trillion, five hundred fifty-five billion, five hundred fifty-one million, three hundred one thousand, two hundred twenty-five".