2106221765 has 16 divisors (see below), whose sum is σ = 2584358400. Its totient is φ = 1647464832.

The previous prime is 2106221737. The next prime is 2106221779. The reversal of 2106221765 is 5671226012.

It is a cyclic number.

It is not a de Polignac number, because 2106221765 - 2¹⁰ = 2106220741 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, 14801 + ... + 66569.

It is an arithmetic number, because the mean of its divisors is an integer number (161522400).

Almost surely, 2^2106221765 is an apocalyptic number.

It is an amenable number.

2106221765 is a deficient number, since it is larger than the sum of its proper divisors (478136635).

2106221765 is a wasteful number, since it uses less digits than its factorization.

2106221765 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51956.

The product of its (nonzero) digits is 10080, while the sum is 32.

The square root of 2106221765 is about 45893.5917639925. The cubic root of 2106221765 is about 1281.8425946754.

Adding to 2106221765 its reverse (5671226012), we get a palindrome (7777447777).

The spelling of 2106221765 in words is "two billion, one hundred six million, two hundred twenty-one thousand, seven hundred sixty-five".