21530155455 has 32 divisors (see below), whose sum is σ = 38282973120. Its totient is φ = 11480607360.

The previous prime is 21530155453. The next prime is 21530155469. The reversal of 21530155455 is 55455103512.

21530155455 is a `hidden beast` number, since 2 + 1 + 53 + 0 + 1 + 554 + 55 = 666.

It is not a de Polignac number, because 21530155455 - 2¹ = 21530155453 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21530155453) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 935385 + ... + 958125.

It is an arithmetic number, because the mean of its divisors is an integer number (1196342910).

Almost surely, 2^21530155455 is an apocalyptic number.

21530155455 is a deficient number, since it is larger than the sum of its proper divisors (16752817665).

21530155455 is a wasteful number, since it uses less digits than its factorization.

21530155455 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29768 (or 29762 counting only the distinct ones).

The product of its (nonzero) digits is 75000, while the sum is 36.

Adding to 21530155455 its reverse (55455103512), we get a palindrome (76985258967).

The spelling of 21530155455 in words is "twenty-one billion, five hundred thirty million, one hundred fifty-five thousand, four hundred fifty-five".