42400009 has 2 divisors, whose sum is σ = 42400010. Its totient is φ = 42400008.

The previous prime is 42399983. The next prime is 42400067. The reversal of 42400009 is 90000424.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 31674384 + 10725625 = 5628^2 + 3275^2 .

It is a cyclic number.

It is not a de Polignac number, because 42400009 - 2¹¹ = 42397961 is a prime.

It is not a weakly prime, because it can be changed into another prime (42400069) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21200004 + 21200005.

It is an arithmetic number, because the mean of its divisors is an integer number (21200005).

Almost surely, 2^42400009 is an apocalyptic number.

It is an amenable number.

42400009 is a deficient number, since it is larger than the sum of its proper divisors (1).

42400009 is an equidigital number, since it uses as much as digits as its factorization.

42400009 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 288, while the sum is 19.

The square root of 42400009 is about 6511.5289295219. The cubic root of 42400009 is about 348.7027049254.

The spelling of 42400009 in words is "forty-two million, four hundred thousand, nine".