21273868449792 has 1296 divisors, whose sum is σ = 75342814092000. Its totient is φ = 5986635153408.

The previous prime is 21273868449721. The next prime is 21273868449811. The reversal of 21273868449792 is 29794486837212.

It is a happy number.

21273868449792 is a `hidden beast` number, since 2 + 1 + 2 + 7 + 38 + 68 + 449 + 7 + 92 = 666.

It is a tau number, because it is divible by the number of its divisors (1296).

It is a Harshad number since it is a multiple of its sum of digits (72).

It is a nude number because it is divisible by every one of its digits.

It is a self number, because there is not a number n which added to its sum of digits gives 21273868449792.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 107 ways as a sum of consecutive naturals, for example, 52014348084 + ... + 52014348492.

Almost surely, 2^{21273868449792} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21273868449792, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37671407046000).

21273868449792 is an abundant number, since it is smaller than the sum of its proper divisors (54068945642208).

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

21273868449792 is an frugal number, since it uses more digits than its factorization.

21273868449792 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 548 (or 500 counting only the distinct ones).

The product of its digits is 585252864, while the sum is 72.

The spelling of 21273868449792 in words is "twenty-one trillion, two hundred seventy-three billion, eight hundred sixty-eight million, four hundred forty-nine thousand, seven hundred ninety-two".