42920209 has 2 divisors, whose sum is σ = 42920210. Its totient is φ = 42920208.

The previous prime is 42920191. The next prime is 42920263. The reversal of 42920209 is 90202924.

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., 22353984 + 20566225 = 4728^2 + 4535^2 .

It is a cyclic number.

It is not a de Polignac number, because 42920209 - 2⁹ = 42919697 is a prime.

It is not a weakly prime, because it can be changed into another prime (42920279) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21460104 + 21460105.

It is an arithmetic number, because the mean of its divisors is an integer number (21460105).

Almost surely, 2^42920209 is an apocalyptic number.

It is an amenable number.

42920209 is a deficient number, since it is larger than the sum of its proper divisors (1).

42920209 is an equidigital number, since it uses as much as digits as its factorization.

42920209 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2592, while the sum is 28.

The square root of 42920209 is about 6551.3516925899. The cubic root of 42920209 is about 350.1229744742.

The spelling of 42920209 in words is "forty-two million, nine hundred twenty thousand, two hundred nine".