640616497 has 2 divisors, whose sum is σ = 640616498. Its totient is φ = 640616496.

The previous prime is 640616461. The next prime is 640616503. The reversal of 640616497 is 794616046.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 409698081 + 230918416 = 20241^2 + 15196^2 .

It is a cyclic number.

It is not a de Polignac number, because 640616497 - 2¹¹ = 640614449 is a prime.

It is not a weakly prime, because it can be changed into another prime (640616297) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320308248 + 320308249.

It is an arithmetic number, because the mean of its divisors is an integer number (320308249).

Almost surely, 2^640616497 is an apocalyptic number.

It is an amenable number.

640616497 is a deficient number, since it is larger than the sum of its proper divisors (1).

640616497 is an equidigital number, since it uses as much as digits as its factorization.

640616497 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 217728, while the sum is 43.

The square root of 640616497 is about 25310.4029402931. The cubic root of 640616497 is about 862.0504960702.

The spelling of 640616497 in words is "six hundred forty million, six hundred sixteen thousand, four hundred ninety-seven".