127638509 has 2 divisors, whose sum is σ = 127638510. Its totient is φ = 127638508.

The previous prime is 127638487. The next prime is 127638521. The reversal of 127638509 is 905836721.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 119355625 + 8282884 = 10925^2 + 2878^2 .

It is a cyclic number.

It is not a de Polignac number, because 127638509 - 2²⁴ = 110861293 is a prime.

It is an alternating number because its digits alternate between odd and even.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (127638559) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 63819254 + 63819255.

It is an arithmetic number, because the mean of its divisors is an integer number (63819255).

Almost surely, 2^127638509 is an apocalyptic number.

It is an amenable number.

127638509 is a deficient number, since it is larger than the sum of its proper divisors (1).

127638509 is an equidigital number, since it uses as much as digits as its factorization.

127638509 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 90720, while the sum is 41.

The square root of 127638509 is about 11297.7214074343. The cubic root of 127638509 is about 503.4935454297.

The spelling of 127638509 in words is "one hundred twenty-seven million, six hundred thirty-eight thousand, five hundred nine".