211912821 has 16 divisors (see below), whose sum is σ = 314184000. Its totient is φ = 141167664.

The previous prime is 211912819. The next prime is 211912829. The reversal of 211912821 is 128219112.

It is not a de Polignac number, because 211912821 - 2¹ = 211912819 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (211912829) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 50610 + ... + 54636.

It is an arithmetic number, because the mean of its divisors is an integer number (19636500).

Almost surely, 2^211912821 is an apocalyptic number.

It is an amenable number.

211912821 is a deficient number, since it is larger than the sum of its proper divisors (102271179).

211912821 is a wasteful number, since it uses less digits than its factorization.

211912821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5985 (or 5979 counting only the distinct ones).

The product of its digits is 576, while the sum is 27.

The square root of 211912821 is about 14557.2257315740. The cubic root of 211912821 is about 596.1914510762.

The spelling of 211912821 in words is "two hundred eleven million, nine hundred twelve thousand, eight hundred twenty-one".