212115865 has 16 divisors (see below), whose sum is σ = 274856400. Its totient is φ = 156218112.

The previous prime is 212115863. The next prime is 212115887. The reversal of 212115865 is 568511212.

It can be written as a sum of positive squares in 8 ways, for example, as 8311689 + 203804176 = 2883^2 + 14276^2 .

It is a cyclic number.

It is not a de Polignac number, because 212115865 - 2¹ = 212115863 is a prime.

It is not an unprimeable number, because it can be changed into a prime (212115863) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 21091 + ... + 29479.

It is an arithmetic number, because the mean of its divisors is an integer number (17178525).

Almost surely, 2^212115865 is an apocalyptic number.

It is an amenable number.

212115865 is a deficient number, since it is larger than the sum of its proper divisors (62740535).

212115865 is a wasteful number, since it uses less digits than its factorization.

212115865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8796.

The product of its digits is 4800, while the sum is 31.

The square root of 212115865 is about 14564.1980555058. The cubic root of 212115865 is about 596.3818036541.

The spelling of 212115865 in words is "two hundred twelve million, one hundred fifteen thousand, eight hundred sixty-five".