40121209 has 4 divisors (see below), whose sum is σ = 41205604. Its totient is φ = 39036816.

The previous prime is 40121203. The next prime is 40121219. The reversal of 40121209 is 90212104.

40121209 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 38688400 + 1432809 = 6220^2 + 1197^2 .

It is a cyclic number.

It is not a de Polignac number, because 40121209 - 2²¹ = 38024057 is a prime.

It is a super-2 number, since 2×40121209² = 3219422823243362, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (40121203) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 542142 + ... + 542215.

It is an arithmetic number, because the mean of its divisors is an integer number (10301401).

Almost surely, 2^40121209 is an apocalyptic number.

It is an amenable number.

40121209 is a deficient number, since it is larger than the sum of its proper divisors (1084395).

40121209 is a wasteful number, since it uses less digits than its factorization.

40121209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1084394.

The product of its (nonzero) digits is 144, while the sum is 19.

The square root of 40121209 is about 6334.1304849206. The cubic root of 40121209 is about 342.3402817913.

The spelling of 40121209 in words is "forty million, one hundred twenty-one thousand, two hundred nine".