211320405 has 24 divisors (see below), whose sum is σ = 366682680. Its totient is φ = 112583040.

The previous prime is 211320401. The next prime is 211320427. The reversal of 211320405 is 504023112.

It can be written as a sum of positive squares in 4 ways, for example, as 127103076 + 84217329 = 11274^2 + 9177^2 .

It is not a de Polignac number, because 211320405 - 2² = 211320401 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (211320401) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 53395 + ... + 57215.

It is an arithmetic number, because the mean of its divisors is an integer number (15278445).

Almost surely, 2^211320405 is an apocalyptic number.

It is an amenable number.

211320405 is a deficient number, since it is larger than the sum of its proper divisors (155362275).

211320405 is a wasteful number, since it uses less digits than its factorization.

211320405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5061 (or 5058 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 211320405 is about 14536.8636576120. The cubic root of 211320405 is about 595.6353686425.

Adding to 211320405 its reverse (504023112), we get a palindrome (715343517).

The spelling of 211320405 in words is "two hundred eleven million, three hundred twenty thousand, four hundred five".