213720 has 64 divisors (see below), whose sum is σ = 695520. Its totient is φ = 52224.

The previous prime is 213713. The next prime is 213721. The reversal of 213720 is 27312.

213720 = T₁₁₅ + T₁₁₆ + ... + T₁₄₀.

213720 is nontrivially palindromic in base 11.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 213720.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (213721) by changing a digit.

213720 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1492 + ... + 1628.

2²¹³⁷²⁰ is an apocalyptic number.

213720 is a gapful number since it is divisible by the number (20) 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 213720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (347760).

213720 is an abundant number, since it is smaller than the sum of its proper divisors (481800).

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

213720 is a wasteful number, since it uses less digits than its factorization.

213720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 164 (or 160 counting only the distinct ones).

The product of its (nonzero) digits is 84, while the sum is 15.

The square root of 213720 is about 462.2986048000. The cubic root of 213720 is about 59.7881417037.

It can be divided in two parts, 21 and 3720, that added together give a triangular number (3741 = T₈₆).

The spelling of 213720 in words is "two hundred thirteen thousand, seven hundred twenty".