211020021009 has 36 divisors (see below), whose sum is σ = 354608825220. Its totient is φ = 120570024960.

The previous prime is 211020020999. The next prime is 211020021011. The reversal of 211020021009 is 900120020112.

It can be written as a sum of positive squares in 2 ways, for example, as 22639716225 + 188380304784 = 150465^2 + 434028^2 .

It is not a de Polignac number, because 211020021009 - 2¹² = 211020016913 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 211020020982 and 211020021000.

It is not an unprimeable number, because it can be changed into a prime (211020031009) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 5453089 + ... + 5491649.

It is an arithmetic number, because the mean of its divisors is an integer number (9850245145).

Almost surely, 2^211020021009 is an apocalyptic number.

It is an amenable number.

211020021009 is a deficient number, since it is larger than the sum of its proper divisors (143588804211).

211020021009 is a wasteful number, since it uses less digits than its factorization.

211020021009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50990 (or 50980 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 18.

The spelling of 211020021009 in words is "two hundred eleven billion, twenty million, twenty-one thousand, nine".