213761 has 4 divisors (see below), whose sum is σ = 215124. Its totient is φ = 212400.

The previous prime is 213751. The next prime is 213791. The reversal of 213761 is 167312.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 87025 + 126736 = 295^2 + 356^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-213761 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a plaindrome in base 11.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 213761.

It is not an unprimeable number, because it can be changed into a prime (213721) 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, 410 + ... + 771.

It is an arithmetic number, because the mean of its divisors is an integer number (53781).

2²¹³⁷⁶¹ is an apocalyptic number.

It is an amenable number.

213761 is a deficient number, since it is larger than the sum of its proper divisors (1363).

213761 is a wasteful number, since it uses less digits than its factorization.

213761 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1362.

The product of its digits is 252, while the sum is 20.

The square root of 213761 is about 462.3429463072. The cubic root of 213761 is about 59.7919647075.

The spelling of 213761 in words is "two hundred thirteen thousand, seven hundred sixty-one".