638940753 has 24 divisors (see below), whose sum is σ = 1034032896. Its totient is φ = 376768800.

The previous prime is 638940719. The next prime is 638940769. The reversal of 638940753 is 357049836.

638940753 is a `hidden beast` number, since 638 + 9 + 4 + 0 + 7 + 5 + 3 = 666.

It is not a de Polignac number, because 638940753 - 2⁶ = 638940689 is a prime.

It is a super-3 number, since 3×638940753³ (a number of 27 digits) contains 333 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 638940699 and 638940708.

It is not an unprimeable number, because it can be changed into a prime (638940773) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 83553 + ... + 90878.

It is an arithmetic number, because the mean of its divisors is an integer number (43084704).

Almost surely, 2^638940753 is an apocalyptic number.

It is an amenable number.

638940753 is a deficient number, since it is larger than the sum of its proper divisors (395092143).

638940753 is a wasteful number, since it uses less digits than its factorization.

638940753 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 174485 (or 174482 counting only the distinct ones).

The product of its (nonzero) digits is 544320, while the sum is 45.

The square root of 638940753 is about 25277.2774048156. The cubic root of 638940753 is about 861.2981804620.

The spelling of 638940753 in words is "six hundred thirty-eight million, nine hundred forty thousand, seven hundred fifty-three".