645998603 has 2 divisors, whose sum is σ = 645998604. Its totient is φ = 645998602.

The previous prime is 645998531. The next prime is 645998621. The reversal of 645998603 is 306899546.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 645998603 - 2¹⁰ = 645997579 is a prime.

It is not a weakly prime, because it can be changed into another prime (645998663) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322999301 + 322999302.

It is an arithmetic number, because the mean of its divisors is an integer number (322999302).

Almost surely, 2^645998603 is an apocalyptic number.

645998603 is a deficient number, since it is larger than the sum of its proper divisors (1).

645998603 is an equidigital number, since it uses as much as digits as its factorization.

645998603 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1399680, while the sum is 50.

The square root of 645998603 is about 25416.5025721479. The cubic root of 645998603 is about 864.4579240327.

The spelling of 645998603 in words is "six hundred forty-five million, nine hundred ninety-eight thousand, six hundred three".