400640663 has 2 divisors, whose sum is σ = 400640664. Its totient is φ = 400640662.

The previous prime is 400640659. The next prime is 400640687. The reversal of 400640663 is 366046004.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 400640663 - 2² = 400640659 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (400640623) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 200320331 + 200320332.

It is an arithmetic number, because the mean of its divisors is an integer number (200320332).

Almost surely, 2^400640663 is an apocalyptic number.

400640663 is a deficient number, since it is larger than the sum of its proper divisors (1).

400640663 is an equidigital number, since it uses as much as digits as its factorization.

400640663 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 10368, while the sum is 29.

The square root of 400640663 is about 20016.0101668639. The cubic root of 400640663 is about 737.1994603452.

Adding to 400640663 its reverse (366046004), we get a palindrome (766686667).

The spelling of 400640663 in words is "four hundred million, six hundred forty thousand, six hundred sixty-three".