213921 has 20 divisors (see below), whose sum is σ = 338800. Its totient is φ = 134136.

The previous prime is 213919. The next prime is 213929. The reversal of 213921 is 129312.

It is a happy number.

It is not a de Polignac number, because 213921 - 2¹ = 213919 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 213894 and 213903.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 213921.

It is not an unprimeable number, because it can be changed into a prime (213929) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 1470 + ... + 1608.

It is an arithmetic number, because the mean of its divisors is an integer number (16940).

2²¹³⁹²¹ is an apocalyptic number.

It is an amenable number.

213921 is a deficient number, since it is larger than the sum of its proper divisors (124879).

213921 is a wasteful number, since it uses less digits than its factorization.

213921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 170 (or 161 counting only the distinct ones).

The product of its digits is 108, while the sum is 18.

The square root of 213921 is about 462.5159456711. The cubic root of 213921 is about 59.8068790720.

The spelling of 213921 in words is "two hundred thirteen thousand, nine hundred twenty-one".