21347221155 has 16 divisors (see below), whose sum is σ = 36782904480. Its totient is φ = 10509401088.

The previous prime is 21347221153. The next prime is 21347221187. The reversal of 21347221155 is 55112274312.

It is a happy number.

It is not a de Polignac number, because 21347221155 - 2¹ = 21347221153 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21347221153) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 54736270 + ... + 54736659.

It is an arithmetic number, because the mean of its divisors is an integer number (2298931530).

Almost surely, 2^21347221155 is an apocalyptic number.

21347221155 is a deficient number, since it is larger than the sum of its proper divisors (15435683325).

21347221155 is a wasteful number, since it uses less digits than its factorization.

21347221155 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 109472950.

The product of its digits is 16800, while the sum is 33.

Adding to 21347221155 its reverse (55112274312), we get a palindrome (76459495467).

The spelling of 21347221155 in words is "twenty-one billion, three hundred forty-seven million, two hundred twenty-one thousand, one hundred fifty-five".