1221000221008 has 10 divisors (see below), whose sum is σ = 2365687928234. Its totient is φ = 610500110496.

The previous prime is 1221000220969. The next prime is 1221000221009. The reversal of 1221000221008 is 8001220001221.

It can be written as a sum of positive squares in only one way, i.e., 1113725630224 + 107274590784 = 1055332^2 + 327528^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221000221009) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38156256891 + ... + 38156256922.

Almost surely, 2^{1221000221008} is an apocalyptic number.

It is an amenable number.

1221000221008 is a deficient number, since it is larger than the sum of its proper divisors (1144687707226).

1221000221008 is an equidigital number, since it uses as much as digits as its factorization.

1221000221008 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 76312513821 (or 76312513815 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 19.

Adding to 1221000221008 its reverse (8001220001221), we get a palindrome (9222220222229).

The spelling of 1221000221008 in words is "one trillion, two hundred twenty-one billion, two hundred twenty-one thousand, eight".