211631421 has 4 divisors (see below), whose sum is σ = 282175232. Its totient is φ = 141087612.

The previous prime is 211631411. The next prime is 211631449. The reversal of 211631421 is 124136112.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 211631421 - 2¹³ = 211623229 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (211631401) by changing a digit.

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, 35271901 + ... + 35271906.

It is an arithmetic number, because the mean of its divisors is an integer number (70543808).

Almost surely, 2^211631421 is an apocalyptic number.

It is an amenable number.

211631421 is a deficient number, since it is larger than the sum of its proper divisors (70543811).

211631421 is an equidigital number, since it uses as much as digits as its factorization.

211631421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 70543810.

The product of its digits is 288, while the sum is 21.

The square root of 211631421 is about 14547.5572176225. The cubic root of 211631421 is about 595.9274390666.

Adding to 211631421 its reverse (124136112), we get a palindrome (335767533).

The spelling of 211631421 in words is "two hundred eleven million, six hundred thirty-one thousand, four hundred twenty-one".