1221221222010 has 80 divisors (see below), whose sum is σ = 3426499017216. Its totient is φ = 311499901152.

The previous prime is 1221221221991. The next prime is 1221221222063. The reversal of 1221221222010 is 102221221221.

It is a happy number.

1221221222010 is a `hidden beast` number, since 1 + 221 + 2 + 212 + 220 + 10 = 666.

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

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 32757034 + ... + 32794293.

Almost surely, 2^{1221221222010} is an apocalyptic number.

1221221222010 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1221221222010 is an abundant number, since it is smaller than the sum of its proper divisors (2205277795206).

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

1221221222010 is a wasteful number, since it uses less digits than its factorization.

1221221222010 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 65551369 (or 65551360 counting only the distinct ones).

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

Adding to 1221221222010 its reverse (102221221221), we get a palindrome (1323442443231).

The spelling of 1221221222010 in words is "one trillion, two hundred twenty-one billion, two hundred twenty-one million, two hundred twenty-two thousand, ten".