638867497 has 4 divisors (see below), whose sum is σ = 676447956. Its totient is φ = 601287040.

The previous prime is 638867483. The next prime is 638867501. The reversal of 638867497 is 794768836.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 304014096 + 334853401 = 17436^2 + 18299^2 .

It is a cyclic number.

It is not a de Polignac number, because 638867497 - 2¹¹ = 638865449 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (638867417) 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 in 3 ways as a sum of consecutive naturals, for example, 18790204 + ... + 18790237.

It is an arithmetic number, because the mean of its divisors is an integer number (169111989).

Almost surely, 2^638867497 is an apocalyptic number.

It is an amenable number.

638867497 is a deficient number, since it is larger than the sum of its proper divisors (37580459).

638867497 is a wasteful number, since it uses less digits than its factorization.

638867497 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37580458.

The product of its digits is 12192768, while the sum is 58.

The square root of 638867497 is about 25275.8283148149. The cubic root of 638867497 is about 861.2652626102.

The spelling of 638867497 in words is "six hundred thirty-eight million, eight hundred sixty-seven thousand, four hundred ninety-seven".