43718821 has 2 divisors, whose sum is σ = 43718822. Its totient is φ = 43718820.

The previous prime is 43718819. The next prime is 43718827. The reversal of 43718821 is 12881734.

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., 38266596 + 5452225 = 6186^2 + 2335^2 .

It is a cyclic number.

It is not a de Polignac number, because 43718821 - 2¹ = 43718819 is a prime.

It is a super-2 number, since 2×43718821² = 3822670619260082, which contains 22 as substring.

Together with 43718819, 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 (43718827) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21859410 + 21859411.

It is an arithmetic number, because the mean of its divisors is an integer number (21859411).

Almost surely, 2^43718821 is an apocalyptic number.

It is an amenable number.

43718821 is a deficient number, since it is larger than the sum of its proper divisors (1).

43718821 is an equidigital number, since it uses as much as digits as its factorization.

43718821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10752, while the sum is 34.

The square root of 43718821 is about 6612.0209467303. The cubic root of 43718821 is about 352.2812109099.

The spelling of 43718821 in words is "forty-three million, seven hundred eighteen thousand, eight hundred twenty-one".