638028776 has 32 divisors (see below), whose sum is σ = 1491497280. Its totient is φ = 248582400.

The previous prime is 638028761. The next prime is 638028779. The reversal of 638028776 is 677820836.

It is a self number, because there is not a number n which added to its sum of digits gives 638028776.

It is not an unprimeable number, because it can be changed into a prime (638028779) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 517265 + ... + 518496.

It is an arithmetic number, because the mean of its divisors is an integer number (46609290).

Almost surely, 2^638028776 is an apocalyptic number.

It is an amenable number.

638028776 is an abundant number, since it is smaller than the sum of its proper divisors (853468504).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

638028776 is a wasteful number, since it uses less digits than its factorization.

638028776 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1035785 (or 1035781 counting only the distinct ones).

The product of its (nonzero) digits is 677376, while the sum is 47.

The square root of 638028776 is about 25259.2315005821. The cubic root of 638028776 is about 860.8882008002. Note that the first 3 decimals are identical.

The spelling of 638028776 in words is "six hundred thirty-eight million, twenty-eight thousand, seven hundred seventy-six".