21215104255 has 16 divisors (see below), whose sum is σ = 25923179520. Its totient is φ = 16664804352.

The previous prime is 21215104241. The next prime is 21215104277. The reversal of 21215104255 is 55240151212.

It is a cyclic number.

It is not a de Polignac number, because 21215104255 - 2²¹ = 21213007103 is a prime.

It is a congruent number.

It is an unprimeable number.

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, 110620 + ... + 233809.

It is an arithmetic number, because the mean of its divisors is an integer number (1620198720).

Almost surely, 2^21215104255 is an apocalyptic number.

21215104255 is a deficient number, since it is larger than the sum of its proper divisors (4708075265).

21215104255 is a wasteful number, since it uses less digits than its factorization.

21215104255 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 344658.

The product of its (nonzero) digits is 4000, while the sum is 28.

Adding to 21215104255 its reverse (55240151212), we get a palindrome (76455255467).

The spelling of 21215104255 in words is "twenty-one billion, two hundred fifteen million, one hundred four thousand, two hundred fifty-five".