42938809 has 2 divisors, whose sum is σ = 42938810. Its totient is φ = 42938808.

The previous prime is 42938807. The next prime is 42938867. The reversal of 42938809 is 90883924.

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., 29942784 + 12996025 = 5472^2 + 3605^2 .

It is a cyclic number.

It is not a de Polignac number, because 42938809 - 2¹ = 42938807 is a prime.

Together with 42938807, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (42938807) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21469404 + 21469405.

It is an arithmetic number, because the mean of its divisors is an integer number (21469405).

Almost surely, 2^42938809 is an apocalyptic number.

It is an amenable number.

42938809 is a deficient number, since it is larger than the sum of its proper divisors (1).

42938809 is an equidigital number, since it uses as much as digits as its factorization.

42938809 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 124416, while the sum is 43.

The square root of 42938809 is about 6552.7710932093. The cubic root of 42938809 is about 350.1735438678.

The spelling of 42938809 in words is "forty-two million, nine hundred thirty-eight thousand, eight hundred nine".