1221012120 has 32 divisors (see below), whose sum is σ = 3663036720. Its totient is φ = 325603200.

The previous prime is 1221012119. The next prime is 1221012137. The reversal of 1221012120 is 212101221.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a junction number, because it is equal to n+sod(n) for n = 1221012096 and 1221012105.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5087431 + ... + 5087670.

Almost surely, 2^1221012120 is an apocalyptic number.

1221012120 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1221012120 is an abundant number, since it is smaller than the sum of its proper divisors (2442024600).

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

1221012120 is a wasteful number, since it uses less digits than its factorization.

1221012120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10175115 (or 10175111 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 12.

The square root of 1221012120 is about 34942.9838451155. The cubic root of 1221012120 is about 1068.8251348977.

Adding to 1221012120 its reverse (212101221), we get a palindrome (1433113341).

The spelling of 1221012120 in words is "one billion, two hundred twenty-one million, twelve thousand, one hundred twenty".