1221001123212 has 36 divisors (see below), whose sum is σ = 3323836392240. Its totient is φ = 375692653152.

The previous prime is 1221001123201. The next prime is 1221001123213. The reversal of 1221001123212 is 2123211001221.

It is a tau number, because it is divible by the number of its divisors (36).

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

It is not an unprimeable number, because it can be changed into a prime (1221001123213) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1304487912 + ... + 1304488847.

Almost surely, 2^{1221001123212} is an apocalyptic number.

1221001123212 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

1221001123212 is an abundant number, since it is smaller than the sum of its proper divisors (2102835269028).

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

1221001123212 is a wasteful number, since it uses less digits than its factorization.

1221001123212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2608976782 (or 2608976777 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 18.

Adding to 1221001123212 its reverse (2123211001221), we get a palindrome (3344212124433).

The spelling of 1221001123212 in words is "one trillion, two hundred twenty-one billion, one million, one hundred twenty-three thousand, two hundred twelve".