638666151 has 4 divisors (see below), whose sum is σ = 851554872. Its totient is φ = 425777432.

The previous prime is 638666141. The next prime is 638666153. The reversal of 638666151 is 151666836.

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

It is a cyclic number.

It is not a de Polignac number, because 638666151 - 2¹³ = 638657959 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638666153) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 106444356 + ... + 106444361.

It is an arithmetic number, because the mean of its divisors is an integer number (212888718).

Almost surely, 2^638666151 is an apocalyptic number.

638666151 is a deficient number, since it is larger than the sum of its proper divisors (212888721).

638666151 is a wasteful number, since it uses less digits than its factorization.

638666151 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 212888720.

The product of its digits is 155520, while the sum is 42.

The square root of 638666151 is about 25271.8450256407. The cubic root of 638666151 is about 861.1747740832.

The spelling of 638666151 in words is "six hundred thirty-eight million, six hundred sixty-six thousand, one hundred fifty-one".