638406247049 has 2 divisors, whose sum is σ = 638406247050. Its totient is φ = 638406247048.

The previous prime is 638406247021. The next prime is 638406247099. The reversal of 638406247049 is 940742604836.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 542937606649 + 95468640400 = 736843^2 + 308980^2 .

It is a cyclic number.

It is not a de Polignac number, because 638406247049 - 2¹⁶ = 638406181513 is a prime.

It is not a weakly prime, because it can be changed into another prime (638406247099) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319203123524 + 319203123525.

It is an arithmetic number, because the mean of its divisors is an integer number (319203123525).

Almost surely, 2^638406247049 is an apocalyptic number.

It is an amenable number.

638406247049 is a deficient number, since it is larger than the sum of its proper divisors (1).

638406247049 is an equidigital number, since it uses as much as digits as its factorization.

638406247049 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6967296, while the sum is 53.

The spelling of 638406247049 in words is "six hundred thirty-eight billion, four hundred six million, two hundred forty-seven thousand, forty-nine".