628780538 has 4 divisors (see below), whose sum is σ = 943170810. Its totient is φ = 314390268.

The previous prime is 628780531. The next prime is 628780541. The reversal of 628780538 is 835087826.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 835087826 = 2 ⋅417543913.

It can be written as a sum of positive squares in only one way, i.e., 525005569 + 103774969 = 22913^2 + 10187^2 .

It is a junction number, because it is equal to n+sod(n) for n = 628780492 and 628780501.

It is not an unprimeable number, because it can be changed into a prime (628780531) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 157195133 + ... + 157195136.

Almost surely, 2^628780538 is an apocalyptic number.

628780538 is a deficient number, since it is larger than the sum of its proper divisors (314390272).

628780538 is a wasteful number, since it uses less digits than its factorization.

628780538 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 314390271.

The product of its (nonzero) digits is 645120, while the sum is 47.

The square root of 628780538 is about 25075.4967647702. The cubic root of 628780538 is about 856.7084101716.

The spelling of 628780538 in words is "six hundred twenty-eight million, seven hundred eighty thousand, five hundred thirty-eight".