645477901 has 2 divisors, whose sum is σ = 645477902. Its totient is φ = 645477900.

The previous prime is 645477893. The next prime is 645477919. The reversal of 645477901 is 109774546.

645477901 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 395015625 + 250462276 = 19875^2 + 15826^2 .

It is a cyclic number.

It is not a de Polignac number, because 645477901 - 2³ = 645477893 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (645477941) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322738950 + 322738951.

It is an arithmetic number, because the mean of its divisors is an integer number (322738951).

Almost surely, 2^645477901 is an apocalyptic number.

It is an amenable number.

645477901 is a deficient number, since it is larger than the sum of its proper divisors (1).

645477901 is an equidigital number, since it uses as much as digits as its factorization.

645477901 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 211680, while the sum is 43.

The square root of 645477901 is about 25406.2571230002. The cubic root of 645477901 is about 864.2255984714.

The spelling of 645477901 in words is "six hundred forty-five million, four hundred seventy-seven thousand, nine hundred one".