400522009 has 4 divisors (see below), whose sum is σ = 400668004. Its totient is φ = 400376016.

The previous prime is 400521971. The next prime is 400522013. The reversal of 400522009 is 900225004.

It is a happy number.

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 106502400 + 294019609 = 10320^2 + 17147^2 .

It is a cyclic number.

It is not a de Polignac number, because 400522009 - 2¹⁹ = 399997721 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (400522039) 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, 68802 + ... + 74395.

It is an arithmetic number, because the mean of its divisors is an integer number (100167001).

Almost surely, 2^400522009 is an apocalyptic number.

It is an amenable number.

400522009 is a deficient number, since it is larger than the sum of its proper divisors (145995).

400522009 is a wasteful number, since it uses less digits than its factorization.

400522009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 145994.

The product of its (nonzero) digits is 720, while the sum is 22.

The square root of 400522009 is about 20013.0459700666. The cubic root of 400522009 is about 737.1266766685.

The spelling of 400522009 in words is "four hundred million, five hundred twenty-two thousand, nine".