628401778 has 4 divisors (see below), whose sum is σ = 942602670. Its totient is φ = 314200888.

The previous prime is 628401757. The next prime is 628401779. The reversal of 628401778 is 877104826.

628401778 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 382319809 + 246081969 = 19553^2 + 15687^2 .

It is a super-2 number, since 2×628401778² = 789777589187122568, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (628401779) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 157100443 + ... + 157100446.

Almost surely, 2^628401778 is an apocalyptic number.

628401778 is a deficient number, since it is larger than the sum of its proper divisors (314200892).

628401778 is a wasteful number, since it uses less digits than its factorization.

628401778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 314200891.

The product of its (nonzero) digits is 150528, while the sum is 43.

The square root of 628401778 is about 25067.9432343382. The cubic root of 628401778 is about 856.5363564721.

The spelling of 628401778 in words is "six hundred twenty-eight million, four hundred one thousand, seven hundred seventy-eight".