61221 has 4 divisors (see below), whose sum is σ = 81632. Its totient is φ = 40812.

The previous prime is 61211. The next prime is 61223. The reversal of 61221 is 12216.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a de Polignac number, because none of the positive numbers 2^k-61221 is a prime.

It is a D-number.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 61197 and 61206.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 61221.

It is not an unprimeable number, because it can be changed into a prime (61223) 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, 10201 + ... + 10206.

It is an arithmetic number, because the mean of its divisors is an integer number (20408).

2⁶¹²²¹ is an apocalyptic number.

It is an amenable number.

61221 is a deficient number, since it is larger than the sum of its proper divisors (20411).

61221 is a wasteful number, since it uses less digits than its factorization.

61221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20410.

The product of its digits is 24, while the sum is 12.

The square root of 61221 is about 247.4287776311. The cubic root of 61221 is about 39.4124536547.

Adding to 61221 its reverse (12216), we get a palindrome (73437).

It can be divided in two parts, 61 and 221, that added together give a palindrome (282).

The spelling of 61221 in words is "sixty-one thousand, two hundred twenty-one".