213951 has 4 divisors (see below), whose sum is σ = 285272. Its totient is φ = 142632.

The previous prime is 213949. The next prime is 213953. The reversal of 213951 is 159312.

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

It is an interprime number because it is at equal distance from previous prime (213949) and next prime (213953).

It is not a de Polignac number, because 213951 - 2¹ = 213949 is a prime.

It is a D-number.

It is a Duffinian number.

213951 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (213953) 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, 35656 + ... + 35661.

It is an arithmetic number, because the mean of its divisors is an integer number (71318).

2²¹³⁹⁵¹ is an apocalyptic number.

213951 is a deficient number, since it is larger than the sum of its proper divisors (71321).

213951 is an equidigital number, since it uses as much as digits as its factorization.

213951 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 71320.

The product of its digits is 270, while the sum is 21.

The square root of 213951 is about 462.5483758484. The cubic root of 213951 is about 59.8096746874.

The spelling of 213951 in words is "two hundred thirteen thousand, nine hundred fifty-one".