638028769 has 4 divisors (see below), whose sum is σ = 729175744. Its totient is φ = 546881796.

The previous prime is 638028761. The next prime is 638028779. The reversal of 638028769 is 967820836.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 638028769 - 2³ = 638028761 is a prime.

It is a super-2 number, since 2×638028769² = 814161420143310722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (638028761) 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, 45573477 + ... + 45573490.

It is an arithmetic number, because the mean of its divisors is an integer number (182293936).

Almost surely, 2^638028769 is an apocalyptic number.

It is an amenable number.

638028769 is a deficient number, since it is larger than the sum of its proper divisors (91146975).

638028769 is an equidigital number, since it uses as much as digits as its factorization.

638028769 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 91146974.

The product of its (nonzero) digits is 870912, while the sum is 49.

The square root of 638028769 is about 25259.2313620189. The cubic root of 638028769 is about 860.8881976519. Note that the first 3 decimals are identical.

The spelling of 638028769 in words is "six hundred thirty-eight million, twenty-eight thousand, seven hundred sixty-nine".