638448149 has 2 divisors, whose sum is σ = 638448150. Its totient is φ = 638448148.

The previous prime is 638448121. The next prime is 638448197. The reversal of 638448149 is 941844836.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 615933124 + 22515025 = 24818^2 + 4745^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-638448149 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (638448199) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319224074 + 319224075.

It is an arithmetic number, because the mean of its divisors is an integer number (319224075).

Almost surely, 2^638448149 is an apocalyptic number.

It is an amenable number.

638448149 is a deficient number, since it is larger than the sum of its proper divisors (1).

638448149 is an equidigital number, since it uses as much as digits as its factorization.

638448149 is an evil number, because the sum of its binary digits is even.

The product of its digits is 663552, while the sum is 47.

The square root of 638448149 is about 25267.5315177403. The cubic root of 638448149 is about 861.0767786033.

The spelling of 638448149 in words is "six hundred thirty-eight million, four hundred forty-eight thousand, one hundred forty-nine".