640055497 has 2 divisors, whose sum is σ = 640055498. Its totient is φ = 640055496.

The previous prime is 640055467. The next prime is 640055587. The reversal of 640055497 is 794550046.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 528034441 + 112021056 = 22979^2 + 10584^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-640055497 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (640055417) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320027748 + 320027749.

It is an arithmetic number, because the mean of its divisors is an integer number (320027749).

Almost surely, 2^640055497 is an apocalyptic number.

It is an amenable number.

640055497 is a deficient number, since it is larger than the sum of its proper divisors (1).

640055497 is an equidigital number, since it uses as much as digits as its factorization.

640055497 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 151200, while the sum is 40.

The square root of 640055497 is about 25299.3181133405. The cubic root of 640055497 is about 861.7987845974.

The spelling of 640055497 in words is "six hundred forty million, fifty-five thousand, four hundred ninety-seven".