645421523 has 2 divisors, whose sum is σ = 645421524. Its totient is φ = 645421522.

The previous prime is 645421501. The next prime is 645421577. The reversal of 645421523 is 325124546.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 645421523 - 2⁸ = 645421267 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 645421523.

It is not a weakly prime, because it can be changed into another prime (645421123) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322710761 + 322710762.

It is an arithmetic number, because the mean of its divisors is an integer number (322710762).

Almost surely, 2^645421523 is an apocalyptic number.

645421523 is a deficient number, since it is larger than the sum of its proper divisors (1).

645421523 is an equidigital number, since it uses as much as digits as its factorization.

645421523 is an evil number, because the sum of its binary digits is even.

The product of its digits is 28800, while the sum is 32.

The square root of 645421523 is about 25405.1475689475. The cubic root of 645421523 is about 864.2004363761.

The spelling of 645421523 in words is "six hundred forty-five million, four hundred twenty-one thousand, five hundred twenty-three".