43155421 has 2 divisors, whose sum is σ = 43155422. Its totient is φ = 43155420.

The previous prime is 43155419. The next prime is 43155439. The reversal of 43155421 is 12455134.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 42758521 + 396900 = 6539^2 + 630^2 .

It is a cyclic number.

It is not a de Polignac number, because 43155421 - 2¹ = 43155419 is a prime.

Together with 43155419, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (43155481) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21577710 + 21577711.

It is an arithmetic number, because the mean of its divisors is an integer number (21577711).

Almost surely, 2^43155421 is an apocalyptic number.

It is an amenable number.

43155421 is a deficient number, since it is larger than the sum of its proper divisors (1).

43155421 is an equidigital number, since it uses as much as digits as its factorization.

43155421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2400, while the sum is 25.

The square root of 43155421 is about 6569.2785753079. The cubic root of 43155421 is about 350.7613927991.

The spelling of 43155421 in words is "forty-three million, one hundred fifty-five thousand, four hundred twenty-one".