8638021657 has 16 divisors (see below), whose sum is σ = 9562769280. Its totient is φ = 7760972032.

The previous prime is 8638021649. The next prime is 8638021669. The reversal of 8638021657 is 7561208368.

It is a cyclic number.

It is not a de Polignac number, because 8638021657 - 2³ = 8638021649 is a prime.

It is not an unprimeable number, because it can be changed into a prime (8638021607) 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 15 ways as a sum of consecutive naturals, for example, 177318 + ... + 220720.

It is an arithmetic number, because the mean of its divisors is an integer number (597673080).

Almost surely, 2^8638021657 is an apocalyptic number.

It is an amenable number.

8638021657 is a deficient number, since it is larger than the sum of its proper divisors (924747623).

8638021657 is a wasteful number, since it uses less digits than its factorization.

8638021657 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43952.

The product of its (nonzero) digits is 483840, while the sum is 46.

The square root of 8638021657 is about 92940.9579087713. The cubic root of 8638021657 is about 2051.8145074390.

The spelling of 8638021657 in words is "eight billion, six hundred thirty-eight million, twenty-one thousand, six hundred fifty-seven".