638667755 has 16 divisors (see below), whose sum is σ = 851853024. Its totient is φ = 455719680.

The previous prime is 638667709. The next prime is 638667773. The reversal of 638667755 is 557766836.

It is a happy number.

638667755 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 638667755 - 2¹⁴ = 638651371 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (53).

It is a junction number, because it is equal to n+sod(n) for n = 638667697 and 638667706.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 106634 + ... + 112463.

It is an arithmetic number, because the mean of its divisors is an integer number (53240814).

Almost surely, 2^638667755 is an apocalyptic number.

638667755 is a deficient number, since it is larger than the sum of its proper divisors (213185269).

638667755 is a wasteful number, since it uses less digits than its factorization.

638667755 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 219166.

The product of its digits is 6350400, while the sum is 53.

The square root of 638667755 is about 25271.8767605415. The cubic root of 638667755 is about 861.1754950249.

The spelling of 638667755 in words is "six hundred thirty-eight million, six hundred sixty-seven thousand, seven hundred fifty-five".