43121999 has 2 divisors, whose sum is σ = 43122000. Its totient is φ = 43121998.

The previous prime is 43121957. The next prime is 43122017. The reversal of 43121999 is 99912134.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 43121999 - 2¹⁶ = 43056463 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (43121929) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21560999 + 21561000.

It is an arithmetic number, because the mean of its divisors is an integer number (21561000).

Almost surely, 2^43121999 is an apocalyptic number.

43121999 is a deficient number, since it is larger than the sum of its proper divisors (1).

43121999 is an equidigital number, since it uses as much as digits as its factorization.

43121999 is an evil number, because the sum of its binary digits is even.

The product of its digits is 17496, while the sum is 38.

The square root of 43121999 is about 6566.7342720716. The cubic root of 43121999 is about 350.6708195898.

The spelling of 43121999 in words is "forty-three million, one hundred twenty-one thousand, nine hundred ninety-nine".