211551065660 has 96 divisors (see below), whose sum is σ = 511809725952. Its totient is φ = 72696293120.

The previous prime is 211551065659. The next prime is 211551065699. The reversal of 211551065660 is 66560155112.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 168122 + ... + 671838.

It is an arithmetic number, because the mean of its divisors is an integer number (5331351312).

Almost surely, 2^211551065660 is an apocalyptic number.

211551065660 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 211551065660, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (255904862976).

211551065660 is an abundant number, since it is smaller than the sum of its proper divisors (300258660292).

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

211551065660 is a wasteful number, since it uses less digits than its factorization.

211551065660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 503843 (or 503841 counting only the distinct ones).

The product of its (nonzero) digits is 54000, while the sum is 38.

The spelling of 211551065660 in words is "two hundred eleven billion, five hundred fifty-one million, sixty-five thousand, six hundred sixty".