6438775690 has 8 divisors (see below), whose sum is σ = 11589796260. Its totient is φ = 2575510272.

The previous prime is 6438775627. The next prime is 6438775691. The reversal of 6438775690 is 965778346.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 6438618081 + 157609 = 80241^2 + 397^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a super-2 number, since 2×6438775690² = 82915664772269952200, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (6438775691) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 321938775 + ... + 321938794.

Almost surely, 2^6438775690 is an apocalyptic number.

6438775690 is a deficient number, since it is larger than the sum of its proper divisors (5151020570).

6438775690 is a wasteful number, since it uses less digits than its factorization.

6438775690 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 643877576.

The product of its (nonzero) digits is 7620480, while the sum is 55.

The square root of 6438775690 is about 80241.9820916707. The cubic root of 6438775690 is about 1860.3775864644.

The spelling of 6438775690 in words is "six billion, four hundred thirty-eight million, seven hundred seventy-five thousand, six hundred ninety".