638773065 has 144 divisors (see below), whose sum is σ = 1380038400. Its totient is φ = 271724544.

The previous prime is 638773061. The next prime is 638773081. The reversal of 638773065 is 560377836.

638773065 is a `hidden beast` number, since 638 + 7 + 7 + 3 + 0 + 6 + 5 = 666.

It is not a de Polignac number, because 638773065 - 2² = 638773061 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 638773065.

It is not an unprimeable number, because it can be changed into a prime (638773061) by changing a digit.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 3309609 + ... + 3309801.

It is an arithmetic number, because the mean of its divisors is an integer number (9583600).

Almost surely, 2^638773065 is an apocalyptic number.

It is an amenable number.

638773065 is an abundant number, since it is smaller than the sum of its proper divisors (741265335).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

638773065 is a wasteful number, since it uses less digits than its factorization.

638773065 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 316 (or 306 counting only the distinct ones).

The product of its (nonzero) digits is 635040, while the sum is 45.

The square root of 638773065 is about 25273.9602160010. The cubic root of 638773065 is about 861.2228255325. Note that the first 3 decimals are identical.

The spelling of 638773065 in words is "six hundred thirty-eight million, seven hundred seventy-three thousand, sixty-five".