40209989 has 2 divisors, whose sum is σ = 40209990. Its totient is φ = 40209988.

The previous prime is 40209943. The next prime is 40210039. The reversal of 40209989 is 98990204.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 38130625 + 2079364 = 6175^2 + 1442^2 .

It is a cyclic number.

It is not a de Polignac number, because 40209989 - 2⁸ = 40209733 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (40208989) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20104994 + 20104995.

It is an arithmetic number, because the mean of its divisors is an integer number (20104995).

Almost surely, 2^40209989 is an apocalyptic number.

It is an amenable number.

40209989 is a deficient number, since it is larger than the sum of its proper divisors (1).

40209989 is an equidigital number, since it uses as much as digits as its factorization.

40209989 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 46656, while the sum is 41.

The square root of 40209989 is about 6341.1346776425. The cubic root of 40209989 is about 342.5926053602.

The spelling of 40209989 in words is "forty million, two hundred nine thousand, nine hundred eighty-nine".