212220405 has 96 divisors (see below), whose sum is σ = 416707200. Its totient is φ = 103203072.

The previous prime is 212220373. The next prime is 212220409. The reversal of 212220405 is 504022212.

It is not a de Polignac number, because 212220405 - 2⁵ = 212220373 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 (212220409) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 669307 + ... + 669623.

It is an arithmetic number, because the mean of its divisors is an integer number (4340700).

Almost surely, 2^212220405 is an apocalyptic number.

It is an amenable number.

212220405 is a deficient number, since it is larger than the sum of its proper divisors (204486795).

212220405 is a wasteful number, since it uses less digits than its factorization.

212220405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 385 (or 373 counting only the distinct ones).

The product of its (nonzero) digits is 320, while the sum is 18.

The square root of 212220405 is about 14567.7865511546. The cubic root of 212220405 is about 596.4797619316.

Adding to 212220405 its reverse (504022212), we get a palindrome (716242617).

The spelling of 212220405 in words is "two hundred twelve million, two hundred twenty thousand, four hundred five".