638797213 has 4 divisors (see below), whose sum is σ = 639367168. Its totient is φ = 638227260.

The previous prime is 638797171. The next prime is 638797223. The reversal of 638797213 is 312797836.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 638797213 - 2¹⁷ = 638666141 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638797223) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 283293 + ... + 285538.

It is an arithmetic number, because the mean of its divisors is an integer number (159841792).

Almost surely, 2^638797213 is an apocalyptic number.

It is an amenable number.

638797213 is a deficient number, since it is larger than the sum of its proper divisors (569955).

638797213 is a wasteful number, since it uses less digits than its factorization.

638797213 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 569954.

The product of its digits is 381024, while the sum is 46.

The square root of 638797213 is about 25274.4379363815. The cubic root of 638797213 is about 861.2336778722.

The spelling of 638797213 in words is "six hundred thirty-eight million, seven hundred ninety-seven thousand, two hundred thirteen".