645371755 has 16 divisors (see below), whose sum is σ = 888459264. Its totient is φ = 440851680.

The previous prime is 645371747. The next prime is 645371759. The reversal of 645371755 is 557173546.

It is not a de Polignac number, because 645371755 - 2³ = 645371747 is a prime.

It is not an unprimeable number, because it can be changed into a prime (645371759) 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 15 ways as a sum of consecutive naturals, for example, 25851 + ... + 44260.

It is an arithmetic number, because the mean of its divisors is an integer number (55528704).

Almost surely, 2^645371755 is an apocalyptic number.

645371755 is a deficient number, since it is larger than the sum of its proper divisors (243087509).

645371755 is a wasteful number, since it uses less digits than its factorization.

645371755 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 70386.

The product of its digits is 441000, while the sum is 43.

The square root of 645371755 is about 25404.1680635285. The cubic root of 645371755 is about 864.1782231757.

The spelling of 645371755 in words is "six hundred forty-five million, three hundred seventy-one thousand, seven hundred fifty-five".