43212121 has 8 divisors (see below), whose sum is σ = 43711304. Its totient is φ = 42716160.

The previous prime is 43212097. The next prime is 43212139. The reversal of 43212121 is 12121234.

43212121 is an esthetic number in base 10, because in such base its adjacent digits differ by 1.

It can be written as a sum of positive squares in 4 ways, for example, as 112896 + 43099225 = 336^2 + 6565^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 43212121 - 2⁵ = 43212089 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 43212095 and 43212104.

It is not an unprimeable number, because it can be changed into a prime (43212151) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 34315 + ... + 35551.

It is an arithmetic number, because the mean of its divisors is an integer number (5463913).

Almost surely, 2^43212121 is an apocalyptic number.

It is an amenable number.

43212121 is a deficient number, since it is larger than the sum of its proper divisors (499183).

43212121 is a wasteful number, since it uses less digits than its factorization.

43212121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1611.

The product of its digits is 96, while the sum is 16.

The square root of 43212121 is about 6573.5927011034. The cubic root of 43212121 is about 350.9149422011.

Adding to 43212121 its reverse (12121234), we get a palindrome (55333355).

The spelling of 43212121 in words is "forty-three million, two hundred twelve thousand, one hundred twenty-one".