628881091 has 4 divisors (see below), whose sum is σ = 631119384. Its totient is φ = 626642800.

The previous prime is 628881067. The next prime is 628881139. The reversal of 628881091 is 190188826.

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

It is a cyclic number.

It is not a de Polignac number, because 628881091 - 2¹⁵ = 628848323 is a prime.

It is a super-3 number, since 3×628881091³ (a number of 27 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (628881041) 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 in 3 ways as a sum of consecutive naturals, for example, 1118725 + ... + 1119286.

It is an arithmetic number, because the mean of its divisors is an integer number (157779846).

Almost surely, 2^628881091 is an apocalyptic number.

628881091 is a deficient number, since it is larger than the sum of its proper divisors (2238293).

628881091 is a wasteful number, since it uses less digits than its factorization.

628881091 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2238292.

The product of its (nonzero) digits is 55296, while the sum is 43.

The square root of 628881091 is about 25077.5016897617. The cubic root of 628881091 is about 856.7540752879.

The spelling of 628881091 in words is "six hundred twenty-eight million, eight hundred eighty-one thousand, ninety-one".