645448939 has 2 divisors, whose sum is σ = 645448940. Its totient is φ = 645448938.

The previous prime is 645448907. The next prime is 645448949. The reversal of 645448939 is 939844546.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 645448939 - 2⁵ = 645448907 is a prime.

It is not a weakly prime, because it can be changed into another prime (645448949) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322724469 + 322724470.

It is an arithmetic number, because the mean of its divisors is an integer number (322724470).

Almost surely, 2^645448939 is an apocalyptic number.

645448939 is a deficient number, since it is larger than the sum of its proper divisors (1).

645448939 is an equidigital number, since it uses as much as digits as its factorization.

645448939 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3732480, while the sum is 52.

The square root of 645448939 is about 25405.6871389065. The cubic root of 645448939 is about 864.2126726087.

The spelling of 645448939 in words is "six hundred forty-five million, four hundred forty-eight thousand, nine hundred thirty-nine".