645235673 has 2 divisors, whose sum is σ = 645235674. Its totient is φ = 645235672.

The previous prime is 645235651. The next prime is 645235699. The reversal of 645235673 is 376532546.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 452497984 + 192737689 = 21272^2 + 13883^2 .

It is a cyclic number.

It is not a de Polignac number, because 645235673 - 2⁸ = 645235417 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 645235673.

It is not a weakly prime, because it can be changed into another prime (645235603) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322617836 + 322617837.

It is an arithmetic number, because the mean of its divisors is an integer number (322617837).

Almost surely, 2^645235673 is an apocalyptic number.

It is an amenable number.

645235673 is a deficient number, since it is larger than the sum of its proper divisors (1).

645235673 is an equidigital number, since it uses as much as digits as its factorization.

645235673 is an evil number, because the sum of its binary digits is even.

The product of its digits is 453600, while the sum is 41.

The square root of 645235673 is about 25401.4895823060. The cubic root of 645235673 is about 864.1174791851.

The spelling of 645235673 in words is "six hundred forty-five million, two hundred thirty-five thousand, six hundred seventy-three".