120891221 has 6 divisors (see below), whose sum is σ = 132880566. Its totient is φ = 109901000.

The previous prime is 120891209. The next prime is 120891229. The reversal of 120891221 is 122198021.

It can be written as a sum of positive squares in only one way, i.e., 92428996 + 28462225 = 9614^2 + 5335^2 .

It is not a de Polignac number, because 120891221 - 2¹⁰ = 120890197 is a prime.

It is a super-2 number, since 2×120891221² = 29229374629741682, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (120891229) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 499430 + ... + 499671.

It is an arithmetic number, because the mean of its divisors is an integer number (22146761).

Almost surely, 2^120891221 is an apocalyptic number.

120891221 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

120891221 is a deficient number, since it is larger than the sum of its proper divisors (11989345).

120891221 is an equidigital number, since it uses as much as digits as its factorization.

120891221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 999123 (or 999112 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 26.

The square root of 120891221 is about 10995.0543882238. The cubic root of 120891221 is about 494.4604821330.

It can be divided in two parts, 1208 and 91221, that added together give a palindrome (92429).

The spelling of 120891221 in words is "one hundred twenty million, eight hundred ninety-one thousand, two hundred twenty-one".