645034778 has 16 divisors (see below), whose sum is σ = 976496640. Its totient is φ = 319543056.

The previous prime is 645034759. The next prime is 645034823. The reversal of 645034778 is 877430546.

645034778 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Smith number, since the sum of its digits (44) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 268808 + ... + 271196.

It is an arithmetic number, because the mean of its divisors is an integer number (61031040).

Almost surely, 2^645034778 is an apocalyptic number.

645034778 is a deficient number, since it is larger than the sum of its proper divisors (331461862).

645034778 is a wasteful number, since it uses less digits than its factorization.

645034778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3581.

The product of its (nonzero) digits is 564480, while the sum is 44.

The square root of 645034778 is about 25397.5348803777. The cubic root of 645034778 is about 864.0277884938.

The spelling of 645034778 in words is "six hundred forty-five million, thirty-four thousand, seven hundred seventy-eight".