111221511837921 has 27 divisors (see below), whose sum is σ = 161690303129043. Its totient is φ = 73672105974480.

The previous prime is 111221511837907. The next prime is 111221511837929. The reversal of 111221511837921 is 129738115122111.

The square root of 111221511837921 is 10546161.

It is a perfect power (a square), and thus also a powerful number.

111221511837921 is a `hidden beast` number, since 1 + 1 + 1 + 221 + 51 + 1 + 8 + 379 + 2 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 32600731187025 + 78620780650896 = 5709705^2 + 8866836^2 .

It is not a de Polignac number, because 111221511837921 - 2¹⁷ = 111221511706849 is a prime.

It is a super-2 number, since 2×111221511837921² (a number of 29 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (111221511837929) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 4967230636 + ... + 4967253026.

Almost surely, 2^{111221511837921} is an apocalyptic number.

111221511837921 is the 10546161-st square number.

111221511837921 is the 5273081-st centered octagonal number.

It is an amenable number.

111221511837921 is a deficient number, since it is larger than the sum of its proper divisors (50468791291122).

111221511837921 is an frugal number, since it uses more digits than its factorization.

111221511837921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45102 (or 22551 counting only the distinct ones).

The product of its digits is 60480, while the sum is 45.

The spelling of 111221511837921 in words is "one hundred eleven trillion, two hundred twenty-one billion, five hundred eleven million, eight hundred thirty-seven thousand, nine hundred twenty-one".