211808781242 has 8 divisors (see below), whose sum is σ = 322065407316. Its totient is φ = 104453645472.

The previous prime is 211808781203. The next prime is 211808781253. The reversal of 211808781242 is 242187808112.

It can be written as a sum of positive squares in 2 ways, for example, as 210120475321 + 1688305921 = 458389^2 + 41089^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a super-2 number, since 2×211808781242² (a number of 23 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 211808781193 and 211808781202.

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 3 ways as a sum of consecutive naturals, for example, 725372393 + ... + 725372684.

Almost surely, 2^211808781242 is an apocalyptic number.

211808781242 is a deficient number, since it is larger than the sum of its proper divisors (110256626074).

211808781242 is a wasteful number, since it uses less digits than its factorization.

211808781242 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1450745152.

The product of its (nonzero) digits is 114688, while the sum is 44.

The spelling of 211808781242 in words is "two hundred eleven billion, eight hundred eight million, seven hundred eighty-one thousand, two hundred forty-two".