1221200021002 has 16 divisors (see below), whose sum is σ = 1983606671592. Its totient is φ = 560516794560.

The previous prime is 1221200020991. The next prime is 1221200021009. The reversal of 1221200021002 is 2001200021221.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 429511147641 + 791688873361 = 655371^2 + 889769^2 .

It is a Harshad number since it is a multiple of its sum of digits (13).

It is not an unprimeable number, because it can be changed into a prime (1221200021009) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 129744553 + ... + 129753964.

Almost surely, 2^{1221200021002} is an apocalyptic number.

1221200021002 is a deficient number, since it is larger than the sum of its proper divisors (762406650590).

1221200021002 is a wasteful number, since it uses less digits than its factorization.

1221200021002 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 259498713.

The product of its (nonzero) digits is 32, while the sum is 13.

Adding to 1221200021002 its reverse (2001200021221), we get a palindrome (3222400042223).

The spelling of 1221200021002 in words is "one trillion, two hundred twenty-one billion, two hundred million, twenty-one thousand, two".