221961 has 8 divisors (see below), whose sum is σ = 298144. Its totient is φ = 146880.

The previous prime is 221957. The next prime is 221987. The reversal of 221961 is 169122.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 221961 - 2² = 221957 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (221941) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 570 + ... + 876.

It is an arithmetic number, because the mean of its divisors is an integer number (37268).

2²²¹⁹⁶¹ is an apocalyptic number.

It is an amenable number.

221961 is a deficient number, since it is larger than the sum of its proper divisors (76183).

221961 is a wasteful number, since it uses less digits than its factorization.

221961 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 551.

The product of its digits is 216, while the sum is 21.

The square root of 221961 is about 471.1273713127. The cubic root of 221961 is about 60.5469435081.

The spelling of 221961 in words is "two hundred twenty-one thousand, nine hundred sixty-one".