1221111002000 has 40 divisors (see below), whose sum is σ = 2952646407672. Its totient is φ = 488444400000.

The previous prime is 1221111001991. The next prime is 1221111002021. The reversal of 1221111002000 is 2001111221.

It can be written as a sum of positive squares in 4 ways, for example, as 84899973376 + 1136211028624 = 291376^2 + 1065932^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is a super-2 number, since 2×1221111002000² (a number of 25 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 305275751 + ... + 305279750.

Almost surely, 2^{1221111002000} is an apocalyptic number.

1221111002000 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1221111002000 is an abundant number, since it is smaller than the sum of its proper divisors (1731535405672).

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

1221111002000 is an equidigital number, since it uses as much as digits as its factorization.

1221111002000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 610555524 (or 610555508 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 11.

Adding to 1221111002000 its reverse (2001111221), we get a palindrome (1223112113221).

The spelling of 1221111002000 in words is "one trillion, two hundred twenty-one billion, one hundred eleven million, two thousand".