21243542913208 has 128 divisors (see below), whose sum is σ = 50123411712000. Its totient is φ = 8199531141120.

The previous prime is 21243542913101. The next prime is 21243542913209. The reversal of 21243542913208 is 80231924534212.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21243542913209) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 531693360 + ... + 531733312.

It is an arithmetic number, because the mean of its divisors is an integer number (391589154000).

Almost surely, 2^{21243542913208} is an apocalyptic number.

21243542913208 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 21243542913208, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25061705856000).

21243542913208 is an abundant number, since it is smaller than the sum of its proper divisors (28879868798792).

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

21243542913208 is a wasteful number, since it uses less digits than its factorization.

21243542913208 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48005 (or 48001 counting only the distinct ones).

The product of its (nonzero) digits is 829440, while the sum is 46.

The spelling of 21243542913208 in words is "twenty-one trillion, two hundred forty-three billion, five hundred forty-two million, nine hundred thirteen thousand, two hundred eight".