215971663844 has 12 divisors (see below), whose sum is σ = 397842538800. Its totient is φ = 102302367048.

The previous prime is 215971663807. The next prime is 215971663847. The reversal of 215971663844 is 448366179512.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 215971663844.

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

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1420866134 + ... + 1420866285.

It is an arithmetic number, because the mean of its divisors is an integer number (33153544900).

Almost surely, 2^215971663844 is an apocalyptic number.

It is an amenable number.

215971663844 is a deficient number, since it is larger than the sum of its proper divisors (181870874956).

215971663844 is a wasteful number, since it uses less digits than its factorization.

215971663844 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2841732442 (or 2841732440 counting only the distinct ones).

The product of its digits is 8709120, while the sum is 56.

The spelling of 215971663844 in words is "two hundred fifteen billion, nine hundred seventy-one million, six hundred sixty-three thousand, eight hundred forty-four".