43721999 has 2 divisors, whose sum is σ = 43722000. Its totient is φ = 43721998.

The previous prime is 43721987. The next prime is 43722023. The reversal of 43721999 is 99912734.

43721999 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 43721999 - 2²⁴ = 26944783 is a prime.

It is a super-2 number, since 2×43721999² = 3823226393112002, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (43721939) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21860999 + 21861000.

It is an arithmetic number, because the mean of its divisors is an integer number (21861000).

Almost surely, 2^43721999 is an apocalyptic number.

43721999 is a deficient number, since it is larger than the sum of its proper divisors (1).

43721999 is an equidigital number, since it uses as much as digits as its factorization.

43721999 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 122472, while the sum is 44.

The square root of 43721999 is about 6612.2612622309. The cubic root of 43721999 is about 352.2897466887.

The spelling of 43721999 in words is "forty-three million, seven hundred twenty-one thousand, nine hundred ninety-nine".