213668 has 24 divisors (see below), whose sum is σ = 460992. Its totient is φ = 84384.

The previous prime is 213659. The next prime is 213713. The reversal of 213668 is 866312.

It is a Harshad number since it is a multiple of its sum of digits (26).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 71 + ... + 657.

It is an arithmetic number, because the mean of its divisors is an integer number (19208).

2²¹³⁶⁶⁸ is an apocalyptic number.

213668 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 213668, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (230496).

213668 is an abundant number, since it is smaller than the sum of its proper divisors (247324).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

213668 is a wasteful number, since it uses less digits than its factorization.

213668 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 611 (or 609 counting only the distinct ones).

The product of its digits is 1728, while the sum is 26.

The square root of 213668 is about 462.2423606724. The cubic root of 213668 is about 59.7832923127.

It can be divided in two parts, 21 and 3668, that multiplied together give a triangular number (77028 = T₃₉₂).

The spelling of 213668 in words is "two hundred thirteen thousand, six hundred sixty-eight".