215971663845 has 32 divisors (see below), whose sum is σ = 396965866752. Its totient is φ = 98218340352.

The previous prime is 215971663807. The next prime is 215971663847. The reversal of 215971663845 is 548366179512.

215971663845 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 215971663845 - 2⁹ = 215971663333 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (215971663847) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 5308422 + ... + 5348951.

It is an arithmetic number, because the mean of its divisors is an integer number (12405183336).

Almost surely, 2^215971663845 is an apocalyptic number.

It is an amenable number.

215971663845 is a deficient number, since it is larger than the sum of its proper divisors (180994202907).

215971663845 is a wasteful number, since it uses less digits than its factorization.

215971663845 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10657581.

The product of its digits is 10886400, while the sum is 57.

The spelling of 215971663845 in words is "two hundred fifteen billion, nine hundred seventy-one million, six hundred sixty-three thousand, eight hundred forty-five".