213551 has 4 divisors (see below), whose sum is σ = 229992. Its totient is φ = 197112.

The previous prime is 213539. The next prime is 213553. The reversal of 213551 is 155312.

213551 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-213551 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (213553) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8201 + ... + 8226.

It is an arithmetic number, because the mean of its divisors is an integer number (57498).

2²¹³⁵⁵¹ is an apocalyptic number.

213551 is a deficient number, since it is larger than the sum of its proper divisors (16441).

213551 is a wasteful number, since it uses less digits than its factorization.

213551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16440.

The product of its digits is 150, while the sum is 17.

The square root of 213551 is about 462.1157863566. The cubic root of 213551 is about 59.7723783055.

Adding to 213551 its reverse (155312), we get a palindrome (368863).

The spelling of 213551 in words is "two hundred thirteen thousand, five hundred fifty-one".