21113680655 has 16 divisors (see below), whose sum is σ = 26899931520. Its totient is φ = 15854019072.

The previous prime is 21113680639. The next prime is 21113680657. The reversal of 21113680655 is 55608631112.

It is a cyclic number.

It is not a de Polignac number, because 21113680655 - 2⁴ = 21113680639 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21113680657) 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, 307220 + ... + 369609.

It is an arithmetic number, because the mean of its divisors is an integer number (1681245720).

Almost surely, 2^21113680655 is an apocalyptic number.

21113680655 is a deficient number, since it is larger than the sum of its proper divisors (5786250865).

21113680655 is a wasteful number, since it uses less digits than its factorization.

21113680655 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 677218.

The product of its (nonzero) digits is 43200, while the sum is 38.

The spelling of 21113680655 in words is "twenty-one billion, one hundred thirteen million, six hundred eighty thousand, six hundred fifty-five".