43131221 has 16 divisors (see below), whose sum is σ = 51542400. Its totient is φ = 36056160.

The previous prime is 43131169. The next prime is 43131223. The reversal of 43131221 is 12213134.

It is not a de Polignac number, because 43131221 - 2²² = 38936917 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 43131221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (43131223) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 12530 + ... + 15596.

It is an arithmetic number, because the mean of its divisors is an integer number (3221400).

Almost surely, 2^43131221 is an apocalyptic number.

43131221 is a gapful number since it is divisible by the number (41) formed by its first and last digit.

It is an amenable number.

43131221 is a deficient number, since it is larger than the sum of its proper divisors (8411179).

43131221 is an equidigital number, since it uses as much as digits as its factorization.

43131221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3129 (or 3115 counting only the distinct ones).

The product of its digits is 144, while the sum is 17.

The square root of 43131221 is about 6567.4364100462. The cubic root of 43131221 is about 350.6958157702.

Adding to 43131221 its reverse (12213134), we get a palindrome (55344355).

The spelling of 43131221 in words is "forty-three million, one hundred thirty-one thousand, two hundred twenty-one".