211012821 has 12 divisors (see below), whose sum is σ = 305048172. Its totient is φ = 140558976.

The previous prime is 211012819. The next prime is 211012829. The reversal of 211012821 is 128210112.

It can be written as a sum of positive squares in 2 ways, for example, as 208484721 + 2528100 = 14439^2 + 1590^2 .

It is not a de Polignac number, because 211012821 - 2¹ = 211012819 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 211012794 and 211012803.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (211012829) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2635 + ... + 20711.

It is an arithmetic number, because the mean of its divisors is an integer number (25420681).

Almost surely, 2^211012821 is an apocalyptic number.

It is an amenable number.

211012821 is a deficient number, since it is larger than the sum of its proper divisors (94035351).

211012821 is a wasteful number, since it uses less digits than its factorization.

211012821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19380 (or 19377 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 18.

The square root of 211012821 is about 14526.2803566501. The cubic root of 211012821 is about 595.3462391732.

Adding to 211012821 its reverse (128210112), we get a palindrome (339222933).

The spelling of 211012821 in words is "two hundred eleven million, twelve thousand, eight hundred twenty-one".