39940409 has 2 divisors, whose sum is σ = 39940410. Its totient is φ = 39940408.

The previous prime is 39940403. The next prime is 39940469. The reversal of 39940409 is 90404993.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 38402809 + 1537600 = 6197^2 + 1240^2 .

It is a cyclic number.

It is not a de Polignac number, because 39940409 - 2¹² = 39936313 is a prime.

It is not a weakly prime, because it can be changed into another prime (39940403) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 19970204 + 19970205.

It is an arithmetic number, because the mean of its divisors is an integer number (19970205).

Almost surely, 2^39940409 is an apocalyptic number.

It is an amenable number.

39940409 is a deficient number, since it is larger than the sum of its proper divisors (1).

39940409 is an equidigital number, since it uses as much as digits as its factorization.

39940409 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 34992, while the sum is 38.

The square root of 39940409 is about 6319.8424822143. The cubic root of 39940409 is about 341.8252729673.

The spelling of 39940409 in words is "thirty-nine million, nine hundred forty thousand, four hundred nine".