21956245243968 has 336 divisors, whose sum is σ = 68157744710400. Its totient is φ = 6219539988480.

The previous prime is 21956245243967. The next prime is 21956245243997. The reversal of 21956245243968 is 86934254265912.

It is a tau number, because it is divible by the number of its divisors (336).

It is a junction number, because it is equal to n+sod(n) for n = 21956245243899 and 21956245243908.

It is not an unprimeable number, because it can be changed into a prime (21956245243967) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 514887928 + ... + 514930568.

Almost surely, 2^{21956245243968} is an apocalyptic number.

21956245243968 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21956245243968, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34078872355200).

21956245243968 is an abundant number, since it is smaller than the sum of its proper divisors (46201499466432).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21956245243968 is a wasteful number, since it uses less digits than its factorization.

21956245243968 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43138 (or 43121 counting only the distinct ones).

The product of its digits is 223948800, while the sum is 66.

The spelling of 21956245243968 in words is "twenty-one trillion, nine hundred fifty-six billion, two hundred forty-five million, two hundred forty-three thousand, nine hundred sixty-eight".