21945812863864 has 64 divisors (see below), whose sum is σ = 42237865692000. Its totient is φ = 10685904929280.

The previous prime is 21945812863861. The next prime is 21945812863873. The reversal of 21945812863864 is 46836821854912.

It is a self number, because there is not a number n which added to its sum of digits gives 21945812863864.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21945812863861) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 286681434 + ... + 286757974.

Almost surely, 2^{21945812863864} is an apocalyptic number.

It is an amenable number.

21945812863864 is a deficient number, since it is larger than the sum of its proper divisors (20292052828136).

21945812863864 is a wasteful number, since it uses less digits than its factorization.

21945812863864 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 82288 (or 82284 counting only the distinct ones).

The product of its digits is 159252480, while the sum is 67.

The spelling of 21945812863864 in words is "twenty-one trillion, nine hundred forty-five billion, eight hundred twelve million, eight hundred sixty-three thousand, eight hundred sixty-four".