2165721095 has 4 divisors (see below), whose sum is σ = 2598865320. Its totient is φ = 1732576872.

The previous prime is 2165721059. The next prime is 2165721127. The reversal of 2165721095 is 5901275612.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 2165721095 - 2¹⁰ = 2165720071 is a prime.

It is a super-2 number, since 2×2165721095² = 9380695722655998050, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 216572105 + ... + 216572114.

It is an arithmetic number, because the mean of its divisors is an integer number (649716330).

Almost surely, 2^2165721095 is an apocalyptic number.

2165721095 is a deficient number, since it is larger than the sum of its proper divisors (433144225).

2165721095 is an equidigital number, since it uses as much as digits as its factorization.

2165721095 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 433144224.

The product of its (nonzero) digits is 37800, while the sum is 38.

The square root of 2165721095 is about 46537.3086351155. The cubic root of 2165721095 is about 1293.8010787709.

The spelling of 2165721095 in words is "two billion, one hundred sixty-five million, seven hundred twenty-one thousand, ninety-five".