21161301605 has 8 divisors (see below), whose sum is σ = 25526513664. Its totient is φ = 16840406800.

The previous prime is 21161301569. The next prime is 21161301613. The reversal of 21161301605 is 50610316112.

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

It is not a de Polignac number, because 21161301605 - 2⁸ = 21161301349 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11078261 + ... + 11080170.

It is an arithmetic number, because the mean of its divisors is an integer number (3190814208).

Almost surely, 2^21161301605 is an apocalyptic number.

It is an amenable number.

21161301605 is a deficient number, since it is larger than the sum of its proper divisors (4365212059).

21161301605 is a wasteful number, since it uses less digits than its factorization.

21161301605 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22158627.

The product of its (nonzero) digits is 1080, while the sum is 26.

Adding to 21161301605 its reverse (50610316112), we get a palindrome (71771617717).

The spelling of 21161301605 in words is "twenty-one billion, one hundred sixty-one million, three hundred one thousand, six hundred five".