21536978337792 has 768 divisors, whose sum is σ = 65998486588320. Its totient is φ = 6758760185856.

The previous prime is 21536978337737. The next prime is 21536978337811. The reversal of 21536978337792 is 29773387963512.

21536978337792 is a `hidden beast` number, since 2 + 1 + 5 + 3 + 6 + 97 + 83 + 377 + 92 = 666.

It is a tau number, because it is divible by the number of its divisors (768).

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

It is a self number, because there is not a number n which added to its sum of digits gives 21536978337792.

It is a congruent number.

It is an unprimeable number.

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 47 ways as a sum of consecutive naturals, for example, 92433383308 + ... + 92433383540.

Almost surely, 2^{21536978337792} 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 21536978337792, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32999243294160).

21536978337792 is an abundant number, since it is smaller than the sum of its proper divisors (44461508250528).

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

21536978337792 is a wasteful number, since it uses less digits than its factorization.

21536978337792 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 546 (or 515 counting only the distinct ones).

The product of its digits is 720135360, while the sum is 72.

The spelling of 21536978337792 in words is "twenty-one trillion, five hundred thirty-six billion, nine hundred seventy-eight million, three hundred thirty-seven thousand, seven hundred ninety-two".