638131011 has 32 divisors (see below), whose sum is σ = 999280128. Its totient is φ = 354620160.

The previous prime is 638131007. The next prime is 638131019. The reversal of 638131011 is 110131836.

It is not a de Polignac number, because 638131011 - 2² = 638131007 is a prime.

It is a super-2 number, since 2×638131011² = 814422374399764242, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (638131019) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 320160 + ... + 322146.

It is an arithmetic number, because the mean of its divisors is an integer number (31227504).

Almost surely, 2^638131011 is an apocalyptic number.

638131011 is a deficient number, since it is larger than the sum of its proper divisors (361149117).

638131011 is a wasteful number, since it uses less digits than its factorization.

638131011 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2411.

The product of its (nonzero) digits is 432, while the sum is 24.

The square root of 638131011 is about 25261.2551350878. The cubic root of 638131011 is about 860.9341800246.

Adding to 638131011 its reverse (110131836), we get a palindrome (748262847).

The spelling of 638131011 in words is "six hundred thirty-eight million, one hundred thirty-one thousand, eleven".