124128221 has 12 divisors (see below), whose sum is σ = 144841788. Its totient is φ = 106065792.

The previous prime is 124128163. The next prime is 124128227. The reversal of 124128221 is 122821421.

It can be written as a sum of positive squares in 2 ways, for example, as 79905721 + 44222500 = 8939^2 + 6650^2 .

It is a de Polignac number, because none of the positive numbers 2^k-124128221 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (124128227) 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, 12755 + ... + 20271.

It is an arithmetic number, because the mean of its divisors is an integer number (12070149).

Almost surely, 2^124128221 is an apocalyptic number.

It is an amenable number.

124128221 is a deficient number, since it is larger than the sum of its proper divisors (20713567).

124128221 is an equidigital number, since it uses as much as digits as its factorization.

124128221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7868 (or 7861 counting only the distinct ones).

The product of its digits is 512, while the sum is 23.

The square root of 124128221 is about 11141.2845309686. The cubic root of 124128221 is about 498.8349152638.

Adding to 124128221 its reverse (122821421), we get a palindrome (246949642).

The spelling of 124128221 in words is "one hundred twenty-four million, one hundred twenty-eight thousand, two hundred twenty-one".