40400309 has 4 divisors (see below), whose sum is σ = 41085120. Its totient is φ = 39715500.

The previous prime is 40400299. The next prime is 40400323. The reversal of 40400309 is 90300404.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 40400309 - 2⁸ = 40400053 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (40400359) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 342317 + ... + 342434.

It is an arithmetic number, because the mean of its divisors is an integer number (10271280).

Almost surely, 2^40400309 is an apocalyptic number.

It is an amenable number.

40400309 is a deficient number, since it is larger than the sum of its proper divisors (684811).

40400309 is an equidigital number, since it uses as much as digits as its factorization.

40400309 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 684810.

The product of its (nonzero) digits is 432, while the sum is 20.

The square root of 40400309 is about 6356.1237401423. The cubic root of 40400309 is about 343.1322691373.

The spelling of 40400309 in words is "forty million, four hundred thousand, three hundred nine".