21026013607872 has 840 divisors, whose sum is σ = 79985769771600. Its totient is φ = 5410035671040.

The previous prime is 21026013607771. The next prime is 21026013607883. The reversal of 21026013607872 is 27870631062012.

21026013607872 is a `hidden beast` number, since 2 + 1 + 0 + 2 + 601 + 36 + 0 + 7 + 8 + 7 + 2 = 666.

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 119 ways as a sum of consecutive naturals, for example, 135312879 + ... + 135468177.

It is an arithmetic number, because the mean of its divisors is an integer number (95221154490).

Almost surely, 2^{21026013607872} 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 21026013607872, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39992884885800).

21026013607872 is an abundant number, since it is smaller than the sum of its proper divisors (58959756163728).

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

21026013607872 is a wasteful number, since it uses less digits than its factorization.

21026013607872 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 155391 (or 155365 counting only the distinct ones).

The product of its (nonzero) digits is 338688, while the sum is 45.

Adding to 21026013607872 its reverse (27870631062012), we get a palindrome (48896644669884).

The spelling of 21026013607872 in words is "twenty-one trillion, twenty-six billion, thirteen million, six hundred seven thousand, eight hundred seventy-two".