645172357 has 2 divisors, whose sum is σ = 645172358. Its totient is φ = 645172356.

The previous prime is 645172349. The next prime is 645172373. The reversal of 645172357 is 753271546.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 560789761 + 84382596 = 23681^2 + 9186^2 .

It is a cyclic number.

It is not a de Polignac number, because 645172357 - 2³ = 645172349 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (645172757) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322586178 + 322586179.

It is an arithmetic number, because the mean of its divisors is an integer number (322586179).

Almost surely, 2^645172357 is an apocalyptic number.

It is an amenable number.

645172357 is a deficient number, since it is larger than the sum of its proper divisors (1).

645172357 is an equidigital number, since it uses as much as digits as its factorization.

645172357 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 176400, while the sum is 40.

The square root of 645172357 is about 25400.2432468668. The cubic root of 645172357 is about 864.0892134137.

The spelling of 645172357 in words is "six hundred forty-five million, one hundred seventy-two thousand, three hundred fifty-seven".