638658213 has 8 divisors (see below), whose sum is σ = 880908000. Its totient is φ = 411090288.

The previous prime is 638658203. The next prime is 638658257. The reversal of 638658213 is 312856836.

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

It is not a de Polignac number, because 638658213 - 2⁶ = 638658149 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638658203) 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, 3670363 + ... + 3670536.

It is an arithmetic number, because the mean of its divisors is an integer number (110113500).

Almost surely, 2^638658213 is an apocalyptic number.

It is an amenable number.

638658213 is a deficient number, since it is larger than the sum of its proper divisors (242249787).

638658213 is a wasteful number, since it uses less digits than its factorization.

638658213 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7340931.

The product of its digits is 207360, while the sum is 42.

The square root of 638658213 is about 25271.6879729075. The cubic root of 638658213 is about 861.1712062131.

The spelling of 638658213 in words is "six hundred thirty-eight million, six hundred fifty-eight thousand, two hundred thirteen".