640980097 has 2 divisors, whose sum is σ = 640980098. Its totient is φ = 640980096.

The previous prime is 640980091. The next prime is 640980139. The reversal of 640980097 is 790089046.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 575952001 + 65028096 = 23999^2 + 8064^2 .

It is a cyclic number.

It is not a de Polignac number, because 640980097 - 2²³ = 632591489 is a prime.

It is not a weakly prime, because it can be changed into another prime (640980091) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320490048 + 320490049.

It is an arithmetic number, because the mean of its divisors is an integer number (320490049).

Almost surely, 2^640980097 is an apocalyptic number.

It is an amenable number.

640980097 is a deficient number, since it is larger than the sum of its proper divisors (1).

640980097 is an equidigital number, since it uses as much as digits as its factorization.

640980097 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 108864, while the sum is 43.

The square root of 640980097 is about 25317.5847386752. The cubic root of 640980097 is about 862.2135589321.

The spelling of 640980097 in words is "six hundred forty million, nine hundred eighty thousand, ninety-seven".