628421786 has 4 divisors (see below), whose sum is σ = 942632682. Its totient is φ = 314210892.

The previous prime is 628421777. The next prime is 628421869. The reversal of 628421786 is 687124826.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 687124826 = 2 ⋅343562413.

It can be written as a sum of positive squares in only one way, i.e., 427207561 + 201214225 = 20669^2 + 14185^2 .

It is a super-2 number, since 2×628421786² = 789827882238859592, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 157105445 + ... + 157105448.

Almost surely, 2^628421786 is an apocalyptic number.

628421786 is a deficient number, since it is larger than the sum of its proper divisors (314210896).

628421786 is a wasteful number, since it uses less digits than its factorization.

628421786 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 314210895.

The product of its digits is 258048, while the sum is 44.

The square root of 628421786 is about 25068.3423065826. The cubic root of 628421786 is about 856.5454469395.

The spelling of 628421786 in words is "six hundred twenty-eight million, four hundred twenty-one thousand, seven hundred eighty-six".