2172215865 has 32 divisors (see below), whose sum is σ = 3549401856. Its totient is φ = 1133999360.

The previous prime is 2172215863. The next prime is 2172215879. The reversal of 2172215865 is 5685122712.

It is not a de Polignac number, because 2172215865 - 2¹ = 2172215863 is a prime.

It is not an unprimeable number, because it can be changed into a prime (2172215863) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 363532 + ... + 369458.

It is an arithmetic number, because the mean of its divisors is an integer number (110918808).

Almost surely, 2^2172215865 is an apocalyptic number.

It is an amenable number.

2172215865 is a deficient number, since it is larger than the sum of its proper divisors (1377185991).

2172215865 is a wasteful number, since it uses less digits than its factorization.

2172215865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6449.

The product of its digits is 67200, while the sum is 39.

The square root of 2172215865 is about 46607.0366468412. The cubic root of 2172215865 is about 1295.0931125687.

The spelling of 2172215865 in words is "two billion, one hundred seventy-two million, two hundred fifteen thousand, eight hundred sixty-five".