645219451 has 2 divisors, whose sum is σ = 645219452. Its totient is φ = 645219450.

The previous prime is 645219413. The next prime is 645219467. The reversal of 645219451 is 154912546.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 645219451 - 2¹¹ = 645217403 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 645219451.

It is not a weakly prime, because it can be changed into another prime (645219251) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322609725 + 322609726.

It is an arithmetic number, because the mean of its divisors is an integer number (322609726).

Almost surely, 2^645219451 is an apocalyptic number.

645219451 is a deficient number, since it is larger than the sum of its proper divisors (1).

645219451 is an equidigital number, since it uses as much as digits as its factorization.

645219451 is an evil number, because the sum of its binary digits is even.

The product of its digits is 43200, while the sum is 37.

The square root of 645219451 is about 25401.1702683164. The cubic root of 645219451 is about 864.1102374739.

The spelling of 645219451 in words is "six hundred forty-five million, two hundred nineteen thousand, four hundred fifty-one".