640454505797 has 2 divisors, whose sum is σ = 640454505798. Its totient is φ = 640454505796.

The previous prime is 640454505793. The next prime is 640454505841. The reversal of 640454505797 is 797505454046.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 443277655681 + 197176850116 = 665791^2 + 444046^2 .

It is a cyclic number.

It is not a de Polignac number, because 640454505797 - 2² = 640454505793 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (640454505791) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320227252898 + 320227252899.

It is an arithmetic number, because the mean of its divisors is an integer number (320227252899).

Almost surely, 2^640454505797 is an apocalyptic number.

It is an amenable number.

640454505797 is a deficient number, since it is larger than the sum of its proper divisors (1).

640454505797 is an equidigital number, since it uses as much as digits as its factorization.

640454505797 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 21168000, while the sum is 56.

The spelling of 640454505797 in words is "six hundred forty billion, four hundred fifty-four million, five hundred five thousand, seven hundred ninety-seven".