638334869 has 4 divisors (see below), whose sum is σ = 638385996. Its totient is φ = 638283744.

The previous prime is 638334817. The next prime is 638334877. The reversal of 638334869 is 968433836.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 514836100 + 123498769 = 22690^2 + 11113^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-638334869 is a prime.

It is a super-2 number, since 2×638334869² = 814942809962494322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638336869) 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, 6947 + ... + 36399.

It is an arithmetic number, because the mean of its divisors is an integer number (159596499).

Almost surely, 2^638334869 is an apocalyptic number.

It is an amenable number.

638334869 is a deficient number, since it is larger than the sum of its proper divisors (51127).

638334869 is a wasteful number, since it uses less digits than its factorization.

638334869 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51126.

The product of its digits is 2239488, while the sum is 50.

The square root of 638334869 is about 25265.2898063727. The cubic root of 638334869 is about 861.0258485749.

The spelling of 638334869 in words is "six hundred thirty-eight million, three hundred thirty-four thousand, eight hundred sixty-nine".