21044161605 has 32 divisors (see below), whose sum is σ = 35097701760. Its totient is φ = 10753783040.

The previous prime is 21044161597. The next prime is 21044161631. The reversal of 21044161605 is 50616144012.

It is not a de Polignac number, because 21044161605 - 2³ = 21044161597 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 127662 + ... + 241631.

It is an arithmetic number, because the mean of its divisors is an integer number (1096803180).

Almost surely, 2^21044161605 is an apocalyptic number.

It is an amenable number.

21044161605 is a deficient number, since it is larger than the sum of its proper divisors (14053540155).

21044161605 is a wasteful number, since it uses less digits than its factorization.

21044161605 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 369461.

The product of its (nonzero) digits is 5760, while the sum is 30.

The spelling of 21044161605 in words is "twenty-one billion, forty-four million, one hundred sixty-one thousand, six hundred five".