638877245 has 4 divisors (see below), whose sum is σ = 766652700. Its totient is φ = 511101792.

The previous prime is 638877229. The next prime is 638877247. The reversal of 638877245 is 542778836.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 404572996 + 234304249 = 20114^2 + 15307^2 .

It is a cyclic number.

It is not a de Polignac number, because 638877245 - 2⁴ = 638877229 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 638877193 and 638877202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638877247) 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, 63887720 + ... + 63887729.

It is an arithmetic number, because the mean of its divisors is an integer number (191663175).

Almost surely, 2^638877245 is an apocalyptic number.

It is an amenable number.

638877245 is a deficient number, since it is larger than the sum of its proper divisors (127775455).

638877245 is a wasteful number, since it uses less digits than its factorization.

638877245 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 127775454.

The product of its digits is 2257920, while the sum is 50.

The square root of 638877245 is about 25276.0211465333. The cubic root of 638877245 is about 861.2696430549.

The spelling of 638877245 in words is "six hundred thirty-eight million, eight hundred seventy-seven thousand, two hundred forty-five".