638697447 has 16 divisors (see below), whose sum is σ = 968225280. Its totient is φ = 415895256.

The previous prime is 638697431. The next prime is 638697457. The reversal of 638697447 is 744796836.

It is a happy number.

It is not a de Polignac number, because 638697447 - 2⁴ = 638697431 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 638697393 and 638697402.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638697427) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 273903 + ... + 276224.

It is an arithmetic number, because the mean of its divisors is an integer number (60514080).

Almost surely, 2^638697447 is an apocalyptic number.

638697447 is a deficient number, since it is larger than the sum of its proper divisors (329527833).

638697447 is a wasteful number, since it uses less digits than its factorization.

638697447 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 550179 (or 550173 counting only the distinct ones).

The product of its digits is 6096384, while the sum is 54.

The square root of 638697447 is about 25272.4642051384. The cubic root of 638697447 is about 861.1888403187.

The spelling of 638697447 in words is "six hundred thirty-eight million, six hundred ninety-seven thousand, four hundred forty-seven".