400444409 has 2 divisors, whose sum is σ = 400444410.
Its totient is φ = 400444408.
The previous prime is 400444403. The next prime is 400444411. The reversal of 400444409 is 904444004.
It is a strong prime.
It can be written as a sum of positive squares in only one way, i.e., 212343184 + 188101225 = 14572^2 + 13715^2
It is a cyclic number.
It is not a de Polignac number, because 400444409 - 220 = 399395833 is a prime.
Together with 400444411, it forms a pair of twin primes.
It is a Chen prime.
It is not a weakly prime, because it can be changed into another prime (400444403) by changing a digit.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 200222204 + 200222205.
It is an arithmetic number, because the mean of its divisors is an integer number (200222205).
Almost surely, 2400444409 is an apocalyptic number.
It is an amenable number.
400444409 is a deficient number, since it is larger than the sum of its proper divisors (1).
400444409 is an equidigital number, since it uses as much as digits as its factorization.
400444409 is an evil number, because the sum of its binary digits is even.
The product of its (nonzero) digits is 9216, while the sum is 29.
The square root of 400444409 is about 20011.1071407856.
The cubic root of 400444409 is about 737.0790681947.
The spelling of 400444409 in words is "four hundred million, four hundred forty-four thousand, four hundred nine".