221121221010 has 128 divisors (see below), whose sum is σ = 561371212800. Its totient is φ = 55651491840.

The previous prime is 221121220993. The next prime is 221121221017. The reversal of 221121221010 is 10122121122.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is not an unprimeable number, because it can be changed into a prime (221121221017) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 37983900 + ... + 37989720.

It is an arithmetic number, because the mean of its divisors is an integer number (4385712600).

Almost surely, 2^221121221010 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 221121221010, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (280685606400).

221121221010 is an abundant number, since it is smaller than the sum of its proper divisors (340249991790).

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

221121221010 is a wasteful number, since it uses less digits than its factorization.

221121221010 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6836.

The product of its (nonzero) digits is 32, while the sum is 15.

Adding to 221121221010 its reverse (10122121122), we get a palindrome (231243342132).

The spelling of 221121221010 in words is "two hundred twenty-one billion, one hundred twenty-one million, two hundred twenty-one thousand, ten".