212211381 has 4 divisors (see below), whose sum is σ = 282948512. Its totient is φ = 141474252.

The previous prime is 212211371. The next prime is 212211397. The reversal of 212211381 is 183112212.

212211381 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 a de Polignac number, because none of the positive numbers 2^k-212211381 is a prime.

It is a super-2 number, since 2×212211381² = 90067340451854322, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (212211331) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 35368561 + ... + 35368566.

It is an arithmetic number, because the mean of its divisors is an integer number (70737128).

Almost surely, 2^212211381 is an apocalyptic number.

It is an amenable number.

212211381 is a deficient number, since it is larger than the sum of its proper divisors (70737131).

212211381 is an equidigital number, since it uses as much as digits as its factorization.

212211381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 70737130.

The product of its digits is 192, while the sum is 21.

The square root of 212211381 is about 14567.4768233898. The cubic root of 212211381 is about 596.4713073414.

Adding to 212211381 its reverse (183112212), we get a palindrome (395323593).

The spelling of 212211381 in words is "two hundred twelve million, two hundred eleven thousand, three hundred eighty-one".