1221116161221 has 36 divisors (see below), whose sum is σ = 1948911095040. Its totient is φ = 736195561200.

The previous prime is 1221116161211. The next prime is 1221116161267. The reversal of 1221116161221 is 1221616111221.

1221116161221 is a `hidden beast` number, since 1 + 2 + 2 + 1 + 11 + 616 + 12 + 21 = 666.

It is not a de Polignac number, because 1221116161221 - 2⁹ = 1221116160709 is a prime.

It is a super-2 number, since 2×1221116161221² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221116161201) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 2727391 + ... + 3143388.

Almost surely, 2^{1221116161221} is an apocalyptic number.

1221116161221 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1221116161221 is a deficient number, since it is larger than the sum of its proper divisors (727794933819).

1221116161221 is a wasteful number, since it uses less digits than its factorization.

1221116161221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5870998 (or 5870984 counting only the distinct ones).

The product of its digits is 576, while the sum is 27.

The spelling of 1221116161221 in words is "one trillion, two hundred twenty-one billion, one hundred sixteen million, one hundred sixty-one thousand, two hundred twenty-one".