40019209 has 6 divisors (see below), whose sum is σ = 40276250. Its totient is φ = 39763776.

The previous prime is 40019179. The next prime is 40019219. The reversal of 40019209 is 90291004.

It can be written as a sum of positive squares in only one way, i.e., 32809984 + 7209225 = 5728^2 + 2685^2 .

It is not a de Polignac number, because 40019209 - 2¹¹ = 40017161 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (40019219) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 31417 + ... + 32665.

Almost surely, 2^40019209 is an apocalyptic number.

It is an amenable number.

40019209 is a deficient number, since it is larger than the sum of its proper divisors (257041).

40019209 is an equidigital number, since it uses as much as digits as its factorization.

40019209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1607 (or 1428 counting only the distinct ones).

The product of its (nonzero) digits is 648, while the sum is 25.

The square root of 40019209 is about 6326.0737428519. The cubic root of 40019209 is about 342.0499254543.

The spelling of 40019209 in words is "forty million, nineteen thousand, two hundred nine".