21115361555 has 8 divisors (see below), whose sum is σ = 25427970672. Its totient is φ = 16832598048.

The previous prime is 21115361537. The next prime is 21115361587. The reversal of 21115361555 is 55516351112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21115361555 - 2¹⁰ = 21115360531 is a prime.

It is a Duffinian 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 7 ways as a sum of consecutive naturals, for example, 7459844 + ... + 7462673.

It is an arithmetic number, because the mean of its divisors is an integer number (3178496334).

Almost surely, 2^21115361555 is an apocalyptic number.

21115361555 is a deficient number, since it is larger than the sum of its proper divisors (4312609117).

21115361555 is a wasteful number, since it uses less digits than its factorization.

21115361555 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14922805.

The product of its digits is 22500, while the sum is 35.

The spelling of 21115361555 in words is "twenty-one billion, one hundred fifteen million, three hundred sixty-one thousand, five hundred fifty-five".