1221220020028 has 6 divisors (see below), whose sum is σ = 2137135035056. Its totient is φ = 610610010012.

The previous prime is 1221220019969. The next prime is 1221220020029. The reversal of 1221220020028 is 8200200221221.

It is a super-2 number, since 2×1221220020028² (a number of 25 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 1221220019990 and 1221220020008.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221220020029) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 152652502500 + ... + 152652502507.

Almost surely, 2^{1221220020028} is an apocalyptic number.

It is an amenable number.

1221220020028 is a deficient number, since it is larger than the sum of its proper divisors (915915015028).

1221220020028 is a wasteful number, since it uses less digits than its factorization.

1221220020028 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 305305005011 (or 305305005009 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 22.

Adding to 1221220020028 its reverse (8200200221221), we get a palindrome (9421420241249).

The spelling of 1221220020028 in words is "one trillion, two hundred twenty-one billion, two hundred twenty million, twenty thousand, twenty-eight".