638078409 has 12 divisors (see below), whose sum is σ = 922357956. Its totient is φ = 425067552.

The previous prime is 638078401. The next prime is 638078411. The reversal of 638078409 is 904870836.

It is a happy number.

638078409 is a `hidden beast` number, since 638 + 0 + 7 + 8 + 4 + 0 + 9 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 469805625 + 168272784 = 21675^2 + 12972^2 .

It is not a de Polignac number, because 638078409 - 2³ = 638078401 is a prime.

It is not an unprimeable number, because it can be changed into a prime (638078401) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 13462 + ... + 38175.

It is an arithmetic number, because the mean of its divisors is an integer number (76863163).

Almost surely, 2^638078409 is an apocalyptic number.

It is an amenable number.

638078409 is a deficient number, since it is larger than the sum of its proper divisors (284279547).

638078409 is a wasteful number, since it uses less digits than its factorization.

638078409 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53016 (or 53013 counting only the distinct ones).

The product of its (nonzero) digits is 290304, while the sum is 45.

The square root of 638078409 is about 25260.2139539633. The cubic root of 638078409 is about 860.9105233860.

The spelling of 638078409 in words is "six hundred thirty-eight million, seventy-eight thousand, four hundred nine".