211521420240 has 160 divisors (see below), whose sum is σ = 706743515520. Its totient is φ = 52023502848.

The previous prime is 211521420223. The next prime is 211521420263. The reversal of 211521420240 is 42024125112.

It is a super-2 number, since 2×211521420240² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 211521420240.

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, 3806899 + ... + 3862061.

It is an arithmetic number, because the mean of its divisors is an integer number (4417146972).

Almost surely, 2^211521420240 is an apocalyptic number.

211521420240 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 211521420240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (353371757760).

211521420240 is an abundant number, since it is smaller than the sum of its proper divisors (495222095280).

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

211521420240 is a wasteful number, since it uses less digits than its factorization.

211521420240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 56421 (or 56415 counting only the distinct ones).

The product of its (nonzero) digits is 1280, while the sum is 24.

Adding to 211521420240 its reverse (42024125112), we get a palindrome (253545545352).

The spelling of 211521420240 in words is "two hundred eleven billion, five hundred twenty-one million, four hundred twenty thousand, two hundred forty".