21105641616 has 40 divisors (see below), whose sum is σ = 56893471680. Its totient is φ = 6729334656.

The previous prime is 21105641603. The next prime is 21105641621. The reversal of 21105641616 is 61614650112.

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, 9557611 + ... + 9559818.

It is an arithmetic number, because the mean of its divisors is an integer number (1422336792).

Almost surely, 2^21105641616 is an apocalyptic number.

It is an amenable number.

21105641616 is an abundant number, since it is smaller than the sum of its proper divisors (35787830064).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21105641616 is a wasteful number, since it uses less digits than its factorization.

21105641616 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19117463 (or 19117457 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 33.

The spelling of 21105641616 in words is "twenty-one billion, one hundred five million, six hundred forty-one thousand, six hundred sixteen".