638540469 has 32 divisors (see below), whose sum is σ = 1082400000. Its totient is φ = 364450752.

The previous prime is 638540453. The next prime is 638540479. The reversal of 638540469 is 964045836.

638540469 is a `hidden beast` number, since 63 + 8 + 540 + 46 + 9 = 666.

It is not a de Polignac number, because 638540469 - 2⁴ = 638540453 is a prime.

It is a super-2 number, since 2×638540469² = 815467861101479922, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638540479) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 230907 + ... + 233655.

It is an arithmetic number, because the mean of its divisors is an integer number (33825000).

Almost surely, 2^638540469 is an apocalyptic number.

It is an amenable number.

638540469 is a deficient number, since it is larger than the sum of its proper divisors (443859531).

638540469 is a wasteful number, since it uses less digits than its factorization.

638540469 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3994 (or 3988 counting only the distinct ones).

The product of its (nonzero) digits is 622080, while the sum is 45.

The square root of 638540469 is about 25269.3583021018. The cubic root of 638540469 is about 861.1182806824.

The spelling of 638540469 in words is "six hundred thirty-eight million, five hundred forty thousand, four hundred sixty-nine".