400320644 has 6 divisors (see below), whose sum is σ = 700561134. Its totient is φ = 200160320.

The previous prime is 400320631. The next prime is 400320659. The reversal of 400320644 is 446023004.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 214271044 + 186049600 = 14638^2 + 13640^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 50040077 + ... + 50040084.

It is an arithmetic number, because the mean of its divisors is an integer number (116760189).

Almost surely, 2^400320644 is an apocalyptic number.

It is an amenable number.

400320644 is a deficient number, since it is larger than the sum of its proper divisors (300240490).

400320644 is a wasteful number, since it uses less digits than its factorization.

400320644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 100080165 (or 100080163 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 23.

The square root of 400320644 is about 20008.0144941971. The cubic root of 400320644 is about 737.0031242446.

Adding to 400320644 its reverse (446023004), we get a palindrome (846343648).

The spelling of 400320644 in words is "four hundred million, three hundred twenty thousand, six hundred forty-four".