400643765 has 4 divisors (see below), whose sum is σ = 480772524. Its totient is φ = 320515008.

The previous prime is 400643753. The next prime is 400643767. The reversal of 400643765 is 567346004.

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 41692849 + 358950916 = 6457^2 + 18946^2 .

It is a cyclic number.

It is not a de Polignac number, because 400643765 - 2²² = 396449461 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (400643767) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 40064372 + ... + 40064381.

It is an arithmetic number, because the mean of its divisors is an integer number (120193131).

Almost surely, 2^400643765 is an apocalyptic number.

It is an amenable number.

400643765 is a deficient number, since it is larger than the sum of its proper divisors (80128759).

400643765 is an equidigital number, since it uses as much as digits as its factorization.

400643765 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80128758.

The product of its (nonzero) digits is 60480, while the sum is 35.

The square root of 400643765 is about 20016.0876546842. The cubic root of 400643765 is about 737.2013629535.

Adding to 400643765 its reverse (567346004), we get a palindrome (967989769).

The spelling of 400643765 in words is "four hundred million, six hundred forty-three thousand, seven hundred sixty-five".