21320106605 has 16 divisors (see below), whose sum is σ = 29255487744. Its totient is φ = 14611259520.

The previous prime is 21320106571. The next prime is 21320106637. The reversal of 21320106605 is 50660102312.

It is not a de Polignac number, because 21320106605 - 2¹⁰ = 21320105581 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 108416 + ... + 233225.

It is an arithmetic number, because the mean of its divisors is an integer number (1828467984).

Almost surely, 2^21320106605 is an apocalyptic number.

It is an amenable number.

21320106605 is a deficient number, since it is larger than the sum of its proper divisors (7935381139).

21320106605 is a wasteful number, since it uses less digits than its factorization.

21320106605 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 343436.

The product of its (nonzero) digits is 2160, while the sum is 26.

Adding to 21320106605 its reverse (50660102312), we get a palindrome (71980208917).

The spelling of 21320106605 in words is "twenty-one billion, three hundred twenty million, one hundred six thousand, six hundred five".