638226971 has 4 divisors (see below), whose sum is σ = 675769752. Its totient is φ = 600684192.

The previous prime is 638226947. The next prime is 638226973. The reversal of 638226971 is 179622836.

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 638226971 - 2⁶ = 638226907 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (638226973) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 18771365 + ... + 18771398.

It is an arithmetic number, because the mean of its divisors is an integer number (168942438).

Almost surely, 2^638226971 is an apocalyptic number.

638226971 is a deficient number, since it is larger than the sum of its proper divisors (37542781).

638226971 is a wasteful number, since it uses less digits than its factorization.

638226971 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37542780.

The product of its digits is 217728, while the sum is 44.

The square root of 638226971 is about 25263.1544150765. The cubic root of 638226971 is about 860.9773326592.

The spelling of 638226971 in words is "six hundred thirty-eight million, two hundred twenty-six thousand, nine hundred seventy-one".