645427999 has 2 divisors, whose sum is σ = 645428000. Its totient is φ = 645427998.

The previous prime is 645427987. The next prime is 645428023. The reversal of 645427999 is 999724546.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-645427999 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (645424999) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322713999 + 322714000.

It is an arithmetic number, because the mean of its divisors is an integer number (322714000).

Almost surely, 2^645427999 is an apocalyptic number.

645427999 is a deficient number, since it is larger than the sum of its proper divisors (1).

645427999 is an equidigital number, since it uses as much as digits as its factorization.

645427999 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4898880, while the sum is 55.

The square root of 645427999 is about 25405.2750231128. The cubic root of 645427999 is about 864.2033267576.

It can be divided in two parts, 6454 and 27999, that added together give a triangular number (34453 = T₂₆₂).

The spelling of 645427999 in words is "six hundred forty-five million, four hundred twenty-seven thousand, nine hundred ninety-nine".