209139435648 has 1536 divisors, whose sum is σ = 809532057600. Its totient is φ = 52553318400.

The previous prime is 209139435613. The next prime is 209139435677. The reversal of 209139435648 is 846534931902.

209139435648 is a `hidden beast` number, since 2 + 0 + 9 + 1 + 39 + 43 + 564 + 8 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a junction number, because it is equal to n+sod(n) for n = 209139435594 and 209139435603.

It is an unprimeable number.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 2864923740 + ... + 2864923812.

It is an arithmetic number, because the mean of its divisors is an integer number (527039100).

Almost surely, 2^209139435648 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 209139435648, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (404766028800).

209139435648 is an abundant number, since it is smaller than the sum of its proper divisors (600392621952).

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

209139435648 is a wasteful number, since it uses less digits than its factorization.

209139435648 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 179 (or 150 counting only the distinct ones).

The product of its (nonzero) digits is 5598720, while the sum is 54.

The spelling of 209139435648 in words is "two hundred nine billion, one hundred thirty-nine million, four hundred thirty-five thousand, six hundred forty-eight".