211720661010 has 48 divisors (see below), whose sum is σ = 582854529816. Its totient is φ = 53137734144.

The previous prime is 211720661003. The next prime is 211720661023. The reversal of 211720661010 is 10166027112.

It is a happy number.

211720661010 is a `hidden beast` number, since 2 + 1 + 17 + 20 + 6 + 610 + 10 = 666.

211720661010 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 155561614569 + 56159046441 = 394413^2 + 236979^2 .

It is a super-2 number, since 2×211720661010² (a number of 23 digits) contains 22 as substring.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 69188229 + ... + 69191288.

Almost surely, 2^211720661010 is an apocalyptic number.

211720661010 is an abundant number, since it is smaller than the sum of its proper divisors (371133868806).

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

211720661010 is a wasteful number, since it uses less digits than its factorization.

211720661010 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 138379547 (or 138379544 counting only the distinct ones).

The product of its (nonzero) digits is 1008, while the sum is 27.

Adding to 211720661010 its reverse (10166027112), we get a palindrome (221886688122).

The spelling of 211720661010 in words is "two hundred eleven billion, seven hundred twenty million, six hundred sixty-one thousand, ten".