40205509 has 2 divisors, whose sum is σ = 40205510. Its totient is φ = 40205508.

The previous prime is 40205507. The next prime is 40205537. The reversal of 40205509 is 90550204.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 30283009 + 9922500 = 5503^2 + 3150^2 .

It is a cyclic number.

It is not a de Polignac number, because 40205509 - 2¹ = 40205507 is a prime.

Together with 40205507, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (40205507) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20102754 + 20102755.

It is an arithmetic number, because the mean of its divisors is an integer number (20102755).

Almost surely, 2^40205509 is an apocalyptic number.

It is an amenable number.

40205509 is a deficient number, since it is larger than the sum of its proper divisors (1).

40205509 is an equidigital number, since it uses as much as digits as its factorization.

40205509 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1800, while the sum is 25.

The square root of 40205509 is about 6340.7814187212. The cubic root of 40205509 is about 342.5798815577.

The spelling of 40205509 in words is "forty million, two hundred five thousand, five hundred nine".