1221002208 has 96 divisors (see below), whose sum is σ = 3676216320. Its totient is φ = 393863040.

The previous prime is 1221002207. The next prime is 1221002213. The reversal of 1221002208 is 8022001221.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (96).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221002201) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3991 + ... + 49577.

It is an arithmetic number, because the mean of its divisors is an integer number (38293920).

Almost surely, 2^1221002208 is an apocalyptic number.

1221002208 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1221002208, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1838108160).

1221002208 is an abundant number, since it is smaller than the sum of its proper divisors (2455214112).

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

1221002208 is a wasteful number, since it uses less digits than its factorization.

1221002208 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45637 (or 45623 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 18.

The square root of 1221002208 is about 34942.8420137802. The cubic root of 1221002208 is about 1068.8222427005.

Adding to 1221002208 its reverse (8022001221), we get a palindrome (9243003429).

The spelling of 1221002208 in words is "one billion, two hundred twenty-one million, two thousand, two hundred eight".