212905 has 24 divisors (see below), whose sum is σ = 328320. Its totient is φ = 131040.

The previous prime is 212903. The next prime is 212909. The reversal of 212905 is 509212.

It is not a de Polignac number, because 212905 - 2¹ = 212903 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is not an unprimeable number, because it can be changed into a prime (212903) 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, 2656 + ... + 2734.

It is an arithmetic number, because the mean of its divisors is an integer number (13680).

2²¹²⁹⁰⁵ is an apocalyptic number.

It is an amenable number.

212905 is a deficient number, since it is larger than the sum of its proper divisors (115415).

212905 is a wasteful number, since it uses less digits than its factorization.

212905 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 109 (or 102 counting only the distinct ones).

The product of its (nonzero) digits is 180, while the sum is 19.

The square root of 212905 is about 461.4162979350. The cubic root of 212905 is about 59.7120461800.

It can be divided in two parts, 21 and 2905, that added together give a triangular number (2926 = T₇₆).

The spelling of 212905 in words is "two hundred twelve thousand, nine hundred five".