21656126016 has 168 divisors, whose sum is σ = 71063794880. Its totient is φ = 6176756736.

The previous prime is 21656125969. The next prime is 21656126017. The reversal of 21656126016 is 61062165612.

21656126016 is a `hidden beast` number, since 21 + 6 + 5 + 612 + 6 + 0 + 16 = 666.

It is a tau number, because it is divible by the number of its divisors (168).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (21656126017) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2491470 + ... + 2500146.

Almost surely, 2^21656126016 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 21656126016, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35531897440).

21656126016 is an abundant number, since it is smaller than the sum of its proper divisors (49407668864).

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

21656126016 is a wasteful number, since it uses less digits than its factorization.

21656126016 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9321 (or 9308 counting only the distinct ones).

The product of its (nonzero) digits is 25920, while the sum is 36.

The spelling of 21656126016 in words is "twenty-one billion, six hundred fifty-six million, one hundred twenty-six thousand, sixteen".