208921212240 has 160 divisors (see below), whose sum is σ = 699858956160. Its totient is φ = 51251017728.

The previous prime is 208921212229. The next prime is 208921212259. The reversal of 208921212240 is 42212129802.

It is a Cunningham number, because it is equal to 457079²-1.

It is a super-2 number, since 2×208921212240² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 799891 + ... + 1028429.

It is an arithmetic number, because the mean of its divisors is an integer number (4374118476).

Almost surely, 2^208921212240 is an apocalyptic number.

208921212240 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 208921212240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (349929478080).

208921212240 is an abundant number, since it is smaller than the sum of its proper divisors (490937743920).

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

208921212240 is a wasteful number, since it uses less digits than its factorization.

208921212240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 228861 (or 228855 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 33.

The spelling of 208921212240 in words is "two hundred eight billion, nine hundred twenty-one million, two hundred twelve thousand, two hundred forty".