21208139345100 has 144 divisors (see below), whose sum is σ = 62602920656640. Its totient is φ = 5541769708800.

The previous prime is 21208139345077. The next prime is 21208139345143. The reversal of 21208139345100 is 154393180212.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 3578334 + ... + 7431066.

It is an arithmetic number, because the mean of its divisors is an integer number (434742504560).

Almost surely, 2^{21208139345100} is an apocalyptic number.

21208139345100 is a gapful number since it is divisible by the number (20) 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 21208139345100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31301460328320).

21208139345100 is an abundant number, since it is smaller than the sum of its proper divisors (41394781311540).

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

21208139345100 is a wasteful number, since it uses less digits than its factorization.

21208139345100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3853120 (or 3853113 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 39.

The spelling of 21208139345100 in words is "twenty-one trillion, two hundred eight billion, one hundred thirty-nine million, three hundred forty-five thousand, one hundred".