43978213 has 2 divisors, whose sum is σ = 43978214. Its totient is φ = 43978212.

The previous prime is 43978211. The next prime is 43978241. The reversal of 43978213 is 31287934.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 40360609 + 3617604 = 6353^2 + 1902^2 .

It is a cyclic number.

It is not a de Polignac number, because 43978213 - 2¹ = 43978211 is a prime.

Together with 43978211, 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 (43978211) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21989106 + 21989107.

It is an arithmetic number, because the mean of its divisors is an integer number (21989107).

Almost surely, 2^43978213 is an apocalyptic number.

It is an amenable number.

43978213 is a deficient number, since it is larger than the sum of its proper divisors (1).

43978213 is an equidigital number, since it uses as much as digits as its factorization.

43978213 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 36288, while the sum is 37.

The square root of 43978213 is about 6631.6071204498. The cubic root of 43978213 is about 352.9765544433.

The spelling of 43978213 in words is "forty-three million, nine hundred seventy-eight thousand, two hundred thirteen".