645139403 has 2 divisors, whose sum is σ = 645139404. Its totient is φ = 645139402.

The previous prime is 645139399. The next prime is 645139447. The reversal of 645139403 is 304931546.

It is a happy number.

645139403 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 is a cyclic number.

It is not a de Polignac number, because 645139403 - 2² = 645139399 is a prime.

It is not a weakly prime, because it can be changed into another prime (645139483) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322569701 + 322569702.

It is an arithmetic number, because the mean of its divisors is an integer number (322569702).

Almost surely, 2^645139403 is an apocalyptic number.

645139403 is a deficient number, since it is larger than the sum of its proper divisors (1).

645139403 is an equidigital number, since it uses as much as digits as its factorization.

645139403 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 38880, while the sum is 35.

The square root of 645139403 is about 25399.5945440080. The cubic root of 645139403 is about 864.0745012310.

It can be divided in two parts, 6451 and 39403, that added together give a palindrome (45854).

The spelling of 645139403 in words is "six hundred forty-five million, one hundred thirty-nine thousand, four hundred three".