1221221010 has 128 divisors (see below), whose sum is σ = 3288625920. Its totient is φ = 288423936.

The previous prime is 1221221003. The next prime is 1221221033. The reversal of 1221221010 is 101221221.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1869844 + ... + 1870496.

It is an arithmetic number, because the mean of its divisors is an integer number (25692390).

Almost surely, 2^1221221010 is an apocalyptic number.

1221221010 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 1221221010, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1644312960).

1221221010 is an abundant number, since it is smaller than the sum of its proper divisors (2067404910).

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

1221221010 is a wasteful number, since it uses less digits than its factorization.

1221221010 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 892.

The product of its (nonzero) digits is 16, while the sum is 12.

The square root of 1221221010 is about 34945.9727293432. The cubic root of 1221221010 is about 1068.8860827370.

Adding to 1221221010 its reverse (101221221), we get a palindrome (1322442231).

The spelling of 1221221010 in words is "one billion, two hundred twenty-one million, two hundred twenty-one thousand, ten".