645003649 has 2 divisors, whose sum is σ = 645003650. Its totient is φ = 645003648.

The previous prime is 645003643. The next prime is 645003683. The reversal of 645003649 is 946300546.

645003649 = T₂₀₇₃₅ + T₂₀₇₃₆ + T₂₀₇₃₇.

It is a happy number.

645003649 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., 510443649 + 134560000 = 22593^2 + 11600^2 .

It is a cyclic number.

It is not a de Polignac number, because 645003649 - 2⁵ = 645003617 is a prime.

It is equal to p_33546934 and since 645003649 and 33546934 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (645003643) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322501824 + 322501825.

It is an arithmetic number, because the mean of its divisors is an integer number (322501825).

Almost surely, 2^645003649 is an apocalyptic number.

645003649 is the 20737-th centered triangular number.

It is an amenable number.

645003649 is a deficient number, since it is larger than the sum of its proper divisors (1).

645003649 is an equidigital number, since it uses as much as digits as its factorization.

645003649 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 77760, while the sum is 37.

The square root of 645003649 is about 25396.9220379163. The cubic root of 645003649 is about 864.0138891121.

The spelling of 645003649 in words is "six hundred forty-five million, three thousand, six hundred forty-nine".