1221001012 has 72 divisors (see below), whose sum is σ = 2719277568. Its totient is φ = 474364800.

The previous prime is 1221000997. The next prime is 1221001051. The reversal of 1221001012 is 2101001221.

It is a self number, because there is not a number n which added to its sum of digits gives 1221001012.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1122733 + ... + 1123819.

It is an arithmetic number, because the mean of its divisors is an integer number (37767744).

Almost surely, 2^1221001012 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1221001012, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1359638784).

1221001012 is an abundant number, since it is smaller than the sum of its proper divisors (1498276556).

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

1221001012 is a wasteful number, since it uses less digits than its factorization.

1221001012 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1637 (or 1628 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 10.

The square root of 1221001012 is about 34942.8249001136. The cubic root of 1221001012 is about 1068.8218937216.

Adding to 1221001012 its reverse (2101001221), we get a palindrome (3322002233).

The spelling of 1221001012 in words is "one billion, two hundred twenty-one million, one thousand, twelve".