638474369 has 4 divisors (see below), whose sum is σ = 687587796. Its totient is φ = 589360944.

The previous prime is 638474351. The next prime is 638474371. The reversal of 638474369 is 963474836.

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 109474369 + 529000000 = 10463^2 + 23000^2 .

It is a cyclic number.

It is not a de Polignac number, because 638474369 - 2⁸ = 638474113 is a prime.

It is a super-2 number, since 2×638474369² = 815299039739896322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (638476369) 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, 24556694 + ... + 24556719.

It is an arithmetic number, because the mean of its divisors is an integer number (171896949).

Almost surely, 2^638474369 is an apocalyptic number.

It is an amenable number.

638474369 is a deficient number, since it is larger than the sum of its proper divisors (49113427).

638474369 is a wasteful number, since it uses less digits than its factorization.

638474369 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 49113426.

The product of its digits is 2612736, while the sum is 50.

The square root of 638474369 is about 25268.0503600891. The cubic root of 638474369 is about 861.0885661040.

The spelling of 638474369 in words is "six hundred thirty-eight million, four hundred seventy-four thousand, three hundred sixty-nine".