43991851 has 2 divisors, whose sum is σ = 43991852. Its totient is φ = 43991850.

The previous prime is 43991809. The next prime is 43991891. The reversal of 43991851 is 15819934.

It is an a-pointer prime, because the next prime (43991891) can be obtained adding 43991851 to its sum of digits (40).

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 43991851 - 2⁷ = 43991723 is a prime.

It is not a weakly prime, because it can be changed into another prime (43991891) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21995925 + 21995926.

It is an arithmetic number, because the mean of its divisors is an integer number (21995926).

Almost surely, 2^43991851 is an apocalyptic number.

43991851 is a deficient number, since it is larger than the sum of its proper divisors (1).

43991851 is an equidigital number, since it uses as much as digits as its factorization.

43991851 is an evil number, because the sum of its binary digits is even.

The product of its digits is 38880, while the sum is 40.

The square root of 43991851 is about 6632.6352982808. The cubic root of 43991851 is about 353.0130376350.

The spelling of 43991851 in words is "forty-three million, nine hundred ninety-one thousand, eight hundred fifty-one".