21503484655 has 4 divisors (see below), whose sum is σ = 25804181592. Its totient is φ = 17202787720.

The previous prime is 21503484641. The next prime is 21503484713. The reversal of 21503484655 is 55648430512.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 21503484655 - 2¹¹ = 21503482607 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 2150348461 + ... + 2150348470.

It is an arithmetic number, because the mean of its divisors is an integer number (6451045398).

Almost surely, 2^21503484655 is an apocalyptic number.

21503484655 is a deficient number, since it is larger than the sum of its proper divisors (4300696937).

21503484655 is an equidigital number, since it uses as much as digits as its factorization.

21503484655 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4300696936.

The product of its (nonzero) digits is 576000, while the sum is 43.

The spelling of 21503484655 in words is "twenty-one billion, five hundred three million, four hundred eighty-four thousand, six hundred fifty-five".