221970 has 48 divisors (see below), whose sum is σ = 623808. Its totient is φ = 50400.

The previous prime is 221957. The next prime is 221987. The reversal of 221970 is 79122.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a Curzon number.

It is an unprimeable number.

221970 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1395 + ... + 1545.

It is an arithmetic number, because the mean of its divisors is an integer number (12996).

2²²¹⁹⁷⁰ is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 221970, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (311904).

221970 is an abundant number, since it is smaller than the sum of its proper divisors (401838).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

221970 is a wasteful number, since it uses less digits than its factorization.

221970 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 175 (or 168 counting only the distinct ones).

The product of its (nonzero) digits is 252, while the sum is 21.

The square root of 221970 is about 471.1369227730. The cubic root of 221970 is about 60.5477618427.

Adding to 221970 its product of nonzero digits (252), we get a palindrome (222222).

The spelling of 221970 in words is "two hundred twenty-one thousand, nine hundred seventy".