638960797 has 2 divisors, whose sum is σ = 638960798. Its totient is φ = 638960796.

The previous prime is 638960771. The next prime is 638960837. The reversal of 638960797 is 797069836.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 535043161 + 103917636 = 23131^2 + 10194^2 .

It is a cyclic number.

It is not a de Polignac number, because 638960797 - 2⁷ = 638960669 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (638960297) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319480398 + 319480399.

It is an arithmetic number, because the mean of its divisors is an integer number (319480399).

Almost surely, 2^638960797 is an apocalyptic number.

It is an amenable number.

638960797 is a deficient number, since it is larger than the sum of its proper divisors (1).

638960797 is an equidigital number, since it uses as much as digits as its factorization.

638960797 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3429216, while the sum is 55.

The square root of 638960797 is about 25277.6738842798. The cubic root of 638960797 is about 861.3071868684.

The spelling of 638960797 in words is "six hundred thirty-eight million, nine hundred sixty thousand, seven hundred ninety-seven".