638278613 has 8 divisors (see below), whose sum is σ = 729825600. Its totient is φ = 546822720.

The previous prime is 638278577. The next prime is 638278631. The reversal of 638278613 is 316872836.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 638278613 - 2⁸ = 638278357 is a prime.

It is a super-3 number, since 3×638278613³ (a number of 27 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638278513) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7028 + ... + 36413.

It is an arithmetic number, because the mean of its divisors is an integer number (91228200).

Almost surely, 2^638278613 is an apocalyptic number.

It is an amenable number.

638278613 is a deficient number, since it is larger than the sum of its proper divisors (91546987).

638278613 is a wasteful number, since it uses less digits than its factorization.

638278613 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45547.

The product of its digits is 290304, while the sum is 44.

The square root of 638278613 is about 25264.1764757928. The cubic root of 638278613 is about 861.0005539657. Note that the first 3 decimals are identical.

The spelling of 638278613 in words is "six hundred thirty-eight million, two hundred seventy-eight thousand, six hundred thirteen".